Happens ( Read about it on a hardware magazine / review website ) but I did not see it ever until recently. Fitted a deepcool gamaxx 200 on a pc powered by core i5 but the damn thing just came out of it's mounting ( 2 legs ). Now I don't know why but can't fit any intel type coolers on that motherboard - mounting holes and every other things looks perfect but still it won't fit. Only solution I presume is to use a cooler which can be bolted on the motherboard like cm hyper 103 / antec a40.
anyway, coming to the topic - sometimes when I tried un-mounting an amd cooler the damn thing also takes out the cpu with it - the bondng between amd cooler and cpu is that much ( used deepcool z5 ) as amd did not provide any bracket / locking mechanism for extra safety of the cpu. So I guessed op must have faced similar situation.
indeed you are right some times back the mechanic removed the Processor for pasting heat sink compound. I don't know whether he fitted rightly