warped manifold, please I need your help

[Skyhawk_au]

Last Dec. I had a manifold leak at the manifold gasket before the turbo.
It cost alot to get fixed. but was happy when it was. Well now the leak is back 8 months later. I don't race my car. It is stock and my daily driver. I called the shop and found out that they didn't resurface the manifold. Or there was no documentation of it being done. Which they were supposed to do. Now they are saying that it is not there problem. Well I see it different because I told them that it was supposed to be done. Well here i am in a he said she said situation. The only way I can hold they accountable at this point is to prove that the proper way to fix a manifold leak is to resurface the manifold. by the way there where also studs broken which from what I understand is common due to Mr2's manifolds warping.
So please is you know where I can find proof that they didn't fix it properly as a shop and were neglegent for not resurfaceing a obviously warped manifold. I would be greatly appreciative.