Yes. I also had several issues with PayPal that ended up with me deleting my account (unauthorized charges that they didn't do anything about). I am still paying for ad-free.
You can use your credit/debit card. It might still route through PayPal, but you can use PayPal without signing up for an account. I'm not sure exactly how it all works, but I know that even after deleting my PayPal account, I'm still on ad-free with no issues. I get the email on the first of each month letting me know it's hitting my card.
Going to "Upgrade to Ad-Free" at the bottom of the page (under the "General Info" tab) should allow you to do this. Perhaps someone more in-tune with how this works might be able to shed more light or help if you have any questions. And, if you can't get anywhere, Jim's advice is the right answer - contact Admin using the "Contact Us" link under "General Info".
Edit to add that my first answer of "Yes" is in response to the OP's question in the post, not the title.
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.