2005 cub cadet slt 1554 belt will not stay on.

The spindles are in great shape and greased. The blades are ome and new. The deck belt is new and ome also. The idler pulley is 4 months old but I suspect the problem is this pulley. The idler spindle does not seem bent and everything looks in alignment but when I turn the pto on the belt is all jumpy and comes off. The belts come off at every selection level. I had just cleaned the debris off the deck on top and on the underside. I just greased all the spindles and check alignment plus spray painted the deck to stop any rust and for looks. I have tried everything I know to do. I have made sure the deck was level also. I think the idler pulley is bad again and I am going to replace it and the tension spring that puts tension on that pulley.

Please let me know what you think may be wrong. I can't get the parts till October first as I am state employee and get paid first of month. Thanks