My account is not being used, and there are no active listings or inventory, however I'm still getting charged fees. I was told to use vacation mode to stop the fees, however Amazon is still putting charges through my credit card. How do I stop it?
Unless you downgrade to the Individual plan, you will continue to get charged the Pro account fees. You'll also be charged for any FBA storage fees, if applicable.
Note that if you downgrade to Individual, you may face reverification if you decide to reupgrade to the Pro plan. Unless you are going to be inactive for a long time, it might be better to pay the fee, rather than have to go through reverification if you go back to the Pro plan (which could take several weeks or even more, which may result in more cost than the fees).