If you are a MasterCard customer, like me, and have any concerns you’d like to bring up with the company they have a very convenient PDF with toll-free numbers for all countries available here:

https://www.mastercard.com/_assets/docs/GlobalServiceTollfreeNumbers.pdf

I was very lucky to be able to find the link, because their customer support number wasn’t advertised anywhere on their website for my country!

This is why monopolies are bad. They tried to deny it, then deferred responsibility when that didn’t work.