Amazon Online seller - lack of customer service

As a Seller, having signed up around October 2025, I was really hoping to be up and running with my Amazon Store. From Day 1 there were Technical issues one after the next. We even had video calls to try sort it out. Eventually in December we managed to sign up and start loading but a lot of the categories were not functioning. By this time I had lost out on Black November and the Christmas shopping rush. I have countless emails of back and forth writing and trying to sort out the stock. Around 17 January I submitted a manual stock list which I was told takes around 2 weeks. We are now well into the first week of February and still no stock has been loaded. I reached out to Customer Service several times. I have potentially lost a lot of sales and potential returning customers. It's an absolute nightmare trying to get answers. I would not recommend signing up with Amazon as a Seller. There appears to be a lot of bugs in their system and a serious lack of concern for helping people getting into selling. I had very high hopes as Amazon is a well known international brand for online shopping. I am so extremely disappointed. I have spent hours perfecting my stock lists, photographs, coding etc only to have gotten nowhere.