Aftermarket exhaust flange angle

[Battercake]

I recently acquired an aftermarket exhaust for my 150cc GY6. It was listed as fitting my model, but upon receipt I found a problem. The flange is welded to the header at a different angle from my original, and as such it won't fit and bolt on. I've already emailed the supplier, who is happy to provide a refund and says that all the pipes they have in stock are the same angle. I personally have no welding experience or equipment and would like to know how much trouble it would be just to get it modified rather than sending it back.

Attached is a photo showing the pipe I received (chrome) and my original (black).