Inauthentic complaints

I do almost 100% online arbitrage. In the past, Amazon seemed to accept about half of my receipts and removed inauthentic complaints from my account as everything is sourced from reputable large retailers. However, in the last 3 months, I don’t think Amazon has accepted any of the receipts and hasn’t removed complaints from my account. I have two questions: 1) Have others doing OA also seen that Amazon hasn’t been accepting receipts to appeal inauthentic complaints? 2) If I acknowledge rather than appeal a complaint, how does that affect the seller account health in the short or long term?