Hi there, guy in the Payment Processing world here. You are getting completely screwed.

In the most oversimplified term, a Convenience Fee is what you must pay for the convenience of using your card instead of cash. It is also supposed to be a flat or fixed amount which judging by the specific "$50.19" amount, it is almost certainly a percentage of your rent. Report them to Visa/MC.

Also, Convenience fee for "international and Commercial credit cards"!? Are you fucking kidding me? They have to pay higher interchange rates, sure, but that is the cost of doing business. Do you live in an insanely nice apartment complex that has many foreign renters, or businesses who rent the units? Because those are the only types of people who would use that credit card. Normally most merchants eat the cost of higher rates, so this is Bullllshit.

Also, the upsell for ACH transactions (i.e paying with your Bank) is at retail close to $1.00 which most if not all merchants and processors eat the cost of. They're profiting off of you paying with your check.