If a creditor tries to settle an account with you that has been charged off, with a monthly payment that is greater than you can afford, what will happen if you send what you can afford, can they proceed with a garnishment, if you are not paying the minimum they are requiring?

Then... you didn't negotiate terms that were suitable for you. You settled on what they said you should be paying back which exceeded expectations. You signed an agreement to pay back a certain amount and you are beholden to that.

if a creditor trys to settle an account with you that has been charged off, with a monthly payment that is greater than you can afford, what will happen if you send what you can afford, can they proceed with a garnishment, if you are not paying the minimum they are requiring?
I think it would depend on the amount of the debt - garnishment means they are going to court - send them what you can and try to work out an affordable repayment plan.