I have all the parts in the parts list but still can't finish the MOC

Hey there! I'm hoping to get some help because i'm genuinely out of ideas. I bought the instructions for a MOC with over 2000 pieces and ordered all of them over bricklink using the rebrickable parts list. Now that i'm builing it however, i'm constantly running into issues with missing parts. And i'm not talking about one or two, i'm missing around 100 total if i had to guess. I already contacted the creator and commented constructive critiscism on the MOC page, no answer. My hunch is that...