Account at Risk

Please advice, my account is at risk.

I’m fairly new to selling on Amazon, I launched a private label product and immediately got a negative product review with only 1 negative review my product was not selling anymore. The reviewer had only 3 reviews, including mine and all were 1* reviews.

For months, I had no sales, I tried to sell at a loss to gain some sales and It worked. I’ve put a lot of effect on this product quality, and my images, description, I believe I raised the bar.

Fast forward a few months, all over sudden the sales picked up and I got two more reviews both 5* and Amazon choice budget. A few days ago a buy posted a seller review of 1*, just as soon as the product was brought and only dispatched on standard shipping, not Amazon Prime. I really don’t believe he/she has received the product yet by the time they gave me the 1* seller feedback. I raised the issue with Amazon and they removed the feedback. As it violates their terms of service, now I thought that was the end of the matter. Today, I’ve received a warning on my seller central account, “Account at Risk”. I checked account health and found the same order details where the negative seller review was removed as a reason for the order defect rate to be over 1% for the last 60 days. To make the matters worst I only sold a few items under 60 so just a one, 1 * review has a huge impact.
A point to note, I’ve really shady competitors manipulating their own reviews. I strongly suspect my product review and now the seller review is the work of the devil.

A little bit about me, I’m a one-person band new to Amazon trying to make it work, I recently retired from my accounting job at a very young age due to illness and this is my sole income. Therefore, I can not afford to lose my account

Please advise how to deal with this issue before they shut my account. Thank you in advance, I highly appreciate every help I get.