Without being able to read the ebay message you received to be sure, those messages indicate non-compliance with the Top Rated Seller policy, not general ebay policy. To maintain top-rated status these days, you have to offer 1-day handling time as well as free returns.
I’ve been selling car parts as well as funnybooks the last few months. It’s a PITA, but despite working full time I’m unsually able to ship books within that strict time frame. In the real world, that means if somebody places an order on the west coast late at night/early morning, I have between the time I wake up and 4:00 pm to get it in the mailbox. (Scheduling a pickup is not an option.)
With bulkier and heavier car parts that require a trip to the P.O., there’s no way I can ship that fast and no way I’ll eat a $25 return on postage for something heavy, so I extended my handling time to 3 days and dumped free returns for those listings, resulting in multiple messages from ebay about top rated seller compliance. My funnybooks display the TRS icon and receive the FVF discount, my car parts do not.