I'm curious... exactly how did the new oil pump fail? I've been turning wrenches on cars & trucks for a very long time, and I've never heard of a new pump failing. As for the timing chain, if in fact the oil pump failed and was not pumping oil... oh yeah, it'll burn that chain up right quick. You replaced the lifters with the camshaft, right?
And as for the oil pump manufacturer being liable... nope. Doesn't work that way. See, you could have paid a shop to rebuild your engine, and then they would be liable. But you wanted to do it yourself, (I understand why) so you are the one responsible for determining if parts are of good quality, clearances are correct, torques are correct... all that important detail stuff. Ain't it fun?
As for advice... use good quality parts, and try it again. Double-check everything. Measure everything. Clean everything like it was surgery. (Shop Tip: cover the top of your workbench with butcher paper; lay the clean parts on that.) Good luck.
The road goes on forever, the party never ends....