XFX 7970 cooler problem

[CrimInalA]

I opened my XFX 7970 since I was getting artifacts very quickly . Not on 925mhz core , but i underclocked vgpu and made a custom fan profile so it would get hotter than 70?C . Else it would get unstable and sometimes show artifacting . Also any augmentation in core voltage would artifact .
So I guessed it was time to look at the paste to see if it still was ok-ish .
Upon my suprise i found a dent in the GPU heatsink positioned almost in the middle of the GPU . The dent is so big i can place a paperclip in it .

Right now the cooler is off and i don't have an idea what to do with this . Lapping,sanding,extra paste .. i feel they're not going to fix this issue .

What would you guys do ?

Preview :

All other pictures here : http://www.skybed.be/temp/xtremesystems/7970dent/