Seller fees on Amazon

Hi, I’m based in the UK and I sell sex toys and accessories on my website. I recently decided to give Amazon a go as business was very slow(I wasn’t focusing on the business due to a personal matter.) The first day I listed my products on Amazon, I got 3 orders. The Amazon fee on each order was different, ranging from 20-30% which is insane. I’ve checked Amazon’s website and most products will incur a 7-15% fee. The only thing that would cost 30% is Amazon experiences. I’m just wondering if they’re overcharging me. I’m on an individual plan so I don’t pay a monthly fee, I pay a flat rate per order. If Amazon is taking 20-30% of my purchase price, plus I need to keep my prices low enough to be within their fair price policy, then how would I be able to make any money? Amazon is trying to take £30 from one of my orders of £143.99 and that sold price was already discounted by 20%. Any guidance would be greatly appreciated.