2 options;
1. when you create classes dont buy heaps of shit then try to save it... buy little things save it then buy again and save the classes, their have been non-save bug's that when you buy like guns/camo/attachment/perks all at once, it won't save properly some time it does but for others it doesn't,
2. If its always occurring restart steam or the game and see how that goes, maybe internet not connecting to your statts well..