You may be in trouble with the first case.

A person orders some goods from you, with delivery included, and authorises full payment.
You get a bad feeling in your water, or whatever, and block delivery, keeping the goods instead.

The purchaser, who had a contract that included delivery, must now turn up in person to collect the goods for the transaction to be concluded. However, it is you who broke the contract by not delivering the goods as agreed, and the purchaser is under no obligation to dance to your tune.

Since you are holding the goods with no intention of delivering them, and also the money, the customer seems to me to be fully justified in instigating a chargeback. That is what they are for - to recover your money when goods are not delivered.

Now, you name the person in public and describe them as dishonest, leaving yourself open to a suit for defamation.

Maybe there is more to it than you have described, but I think you may need to consider doing some rapid back-pedalling, or getting on the phone to your solicitor.