I'm sorry, we haven't been having a fun time with WHMCS. They rolled out a less than stellar update, that caused some major billing problems. We also had additional problems with some other third party addons. We cut out some of the problematic modules and wrote our own code to fix it all, but there was still a specific issue with how WHMCS handles cancellations. People with invoices due since 11/26/2019 who cancelled may be affected.
We will honor all refunds if you placed a cancellation request and got charged, and we're going to look through these ourselves to refund people that shouldn't have been charged.
Luckily it's not as bad as last year where WHMCS tried charging people 5 times.