Amazon fraud transactions

Today there are four unauthorised transactions from my account via komparify(gift card retailer). I lost about 500 from my account through gift cards. I complained to amazon they recorded only three transactions as complaint idk why they took that I got sg only for 3 transactions (95,102,203). I haven’t seen their response that much interesting. they are saying that I have shared the username and password. but I have logged only on my laptop and mobile