Rogue pharmacy

This is the worst and most pathetic service I received from a pharmacy, an incorrect inhaler was sent to me to which I called them and a collection was organized item was sent back to pharmacy to which they received but from last year I am getting messages demanding payment for an item they got back and threats to affect my credit score , just reached out now again and spoke to a chat agent Michelle who was rude and blunt and no customer service ethic who just stated I need to make payment .how can anyone pay 900 plus for an item that was sent back does this company think people have money for nothing .pathetic service disgusted with customer service reps. 1st call center who is such rogues