I am planning to start offering credit card payments as well, but the tenant would have to pay the transaction charge for that.

I nearly had a heart attack but after rereading your email I could see you were still in charge.

they charge huge penalty fees for minor infractions knowing someone will have to pay.

No charge to the investor.

What do they charge?

Have a clause in their lease that states something like "On the 6th day of the month, if the rent has not been paid, the tenant agrees to have their credit card charged for the total rent amount, plus a $50 late fee, as well as any credit card processing charges."

I researched the property at the Court House and found out National City charged off her account.

My new plan is to not advertise that they are included, and then charge an extra $25/month if they want one installed.

Just to give you a few comparison: Equity Trust Co has tiered fee schedule - for $50k to $100k, they charge $360/yr, and increases as your account increases in value; a bit less for <50K.

If through a listing broker it will depend on what the listing broker entered on the MLS and MLS rules.In Georgia for instance on FMLS if as a broker you screw up and enter commission wrong,mistake things etc. you can be on the hook for the commission or lose access to the MLS.MLS's are sometimes controlled by REALTOR associations and other times are private entities that are non-profits or for-profit organizations.Also the brokers/agents involved it would matter if they were REALTORS or not.Generally your state's real estate commission does not handle commission disputes.They only care about license laws.The agent can argue procuring cause with the other agent but it should not stop your sale.Simply you would close and get your proceeds and the commission in question would be froze until a solution was given and signed in writing or a court order.There are so many variables to this and it is state specific.Procuring cause is a chain of events leading up to a sale of a property.If the chain is broken generally the broker/agents is not due a commission.The moral of the whole story is the buyers agent needs to learn how to protect themselves in the future.I am not going to court to get my agents commission when I only charge them a 300 flat fee as a broker.No legal advice