Anyway, their SSL certificate expired, as it naturally does with enterprise webs.

All (most?) online transactions with certain class of MasterCard cards were completely SOL at that moment.

They did not renew the cert for more than a year. No amount of communication attempts with MasterCard could help, neither from customers (me) nor from banks' IT departments. Then they just quietly dropped the service altogether.

While I was poking I have found that the service is written in microsoft-something (IIS), certificate chain was unusually long with intermediates which I never heard of and all of that is hosted in a third-world country quite far away from Ukraine. But that's another story.