CLEVELAND — The bill has come due, and the account is overdrawn. That’s where we’re at with a Cleveland Cavaliers team that didn’t handle its business properly in the first two rounds of these playoffs.Now there’s nothing left.Nothing left in their legs. Nothing left to celebrate. Nothing left to say.No team in NBA history has ever come back from a 3-0 deficit, and this certainly doesn’t look like the squad that will be the first. Cleveland’s dismal fourth-quarter effort in Saturday’s 121-108 loss to the New York Knicks in Game 3 of the Eastern Conference finals was a disgrace. They looked like a team that has quit.Fatigue has been a major theme in this series, and there’s little doubt the Cavs are exhausted, but a lot of that is their fault. They’ve played 13 games in 25 days because they allowed both of their previous series to reach seven games.“We did it to ourselves,” Donovan Mitchell said.He’s absolutely right.They were the more talented team in the first round and should’ve disposed of the Toronto Raptors in five games. They should’ve beaten the Detroit Pistons in six.Had the Cavs closed out the Pistons in Game 6 at home, their first game against the Knicks in these conference finals would’ve been last Sunday, when they looked terrific in closing out the Pistons. Maybe they don’t blow a 22-point lead in the second half of Game 1 against the Knicks if it was last Sunday.Had they beaten the Pistons in six, they would’ve had three days off to rest before Saturday’s Game 3. This could’ve been a different series. Maybe.Of course, we’ll never know. What we’re left with is players who look as if they’ve given up. They never led in Game 3. They didn’t get a fast-break basket until the fourth quarter and were outscored 17-4 in fast-break points. Mitchell and James Harden combined to shoot 4 of 17 on 3-pointers. Their legs are gone. So is their spirit.“I did think their physicality and energy level was much higher than ours,” Cavs coach Kenny Atkinson said. “Kind of just call it what it is. Credit to them. I thought their physicality got us.”Atkinson has had a miserable conference finals, beginning with the timeout debacle in the second half of Game 1. Mitchell hasn’t looked like himself for much of this postseason.He hasn’t shot it well. He has no burst. Everyone continues to insist he is healthy, which makes this worse. Either they’re lying or there’s something larger going on. He’s had his share of May injuries in the past, but he’s never looked like … this.Against Toronto, the excuse was the junk defenses the Raptors sent at him. Unorthodox traps from unorthodox angles. Against Detroit, it was dealing with Ausar Thompson, one of the league’s best defenders.What is it now? What’s left? Why can’t he get past Knicks defenders? Why is he 9 of 28 from 3 in this series? Is it really just dead legs? Is that really a viable excuse at this point?He seemed to grimace after getting fouled in the first half Saturday night and limped around the court momentarily. Injuries are part of who he has been in the playoffs since he came to Cleveland. If they’re going to declare him healthy, we have to take them at their word, at least for now.The Cavs have been positioning themselves all season to present Mitchell with a new four-year extension worth about $277 million this summer. As he nears his 30th birthday this fall, he has not looked in this postseason like a player worth that type of investment.He remains the most important player on this roster, but he has struggled to adapt alongside Harden. One of the biggest questions following the trade to bring Harden to Cleveland was whether their games could coexist. Both stars wanted this to happen, and both have been eager to make it work. Nevertheless, it has been clumsy at times in these playoffs.Harden plays a specific style of pick-and-roll that is a slow pace and doesn’t require a lot of motion. It can be difficult for teammates who aren’t used to that style. Mitchell typically plays at a faster tempo. To his credit, Mitchell has tried adapting to Harden. In the series against Detroit, while Thompson was guarding him, Mitchell’s cutting and constant motion drew Thompson into the play and allowed him to get close enough to Harden for a key steal late in the game. The Cavs’ solution was for Mitchell to stop moving and go to the other side of the court whenever Thompson was guarding him.For as lousy as Harden looked early in the Detroit series, most of the Cavs’ best looks in this series with the Knicks have come with him, not Mitchell, running the offense. The Cavs have tried staggering the two stars’ minutes as best they can, but there is going to be inevitable overlap. None of it is working. Mitchell’s rhythm is off whether Harden is on the court or not.Making it to the conference finals was a breakthrough for this organization and worth celebrating, but the players’ energy and effort since they got here leave plenty to be desired.An important offseason awaits, with contract decisions to make on Mitchell and Harden and the inevitable debate on whether to pursue Giannis Antetokounmpo. LeBron James looms over all of this, too.Despite reaching the conference finals, a maddeningly inconsistent team throughout the regular season and the playoffs now has a losing postseason record (8-9).New York fans, meanwhile, descended on Cleveland by the thousands for Game 3. Mitchell grew up a Knicks fan 45 minutes from Manhattan and once thought he was heading back home before the Cavs swooped in and acquired him.Mitchell has routinely been adorned with “M-V-P” chants in Rocket Arena over the years. This time, with the game long decided and Cavs fans heading home, Mitchell was merely a bystander as Jalen Brunson stepped to the free-throw line in the fourth quarter to boisterous “M-V-P” chants. Cleveland historically has one of the best home-court advantages in the NBA, but on this night, it had fallen into enemy hands. The Knicks’ takeover was complete.First, they took the Cavs’ seats. Then they took their hearts.