You only have to pay any debt once--it doesn't matter how often or how many people try to collect. You want to make sure you pay the correct party, though; let each agency know, in writing, in some way that you can prove delivery (e.g. fedex or certified mail, return receipt requested) that you are being charged by another agency as well and cannot pay until it is determined who is the lawful recipient of the debt. Copy the hospital, too. Ask each agency to provide full documentation of the debt--exactly which services, procedures, etc. they are collecting for--and their authority to collect. Ask the hospital to send you a statement of all amounts owed and to also verify who has authority to collect. Then compare all documention and determine how much you lawfully owe to whom.