Help with bill

Hello so I need some help! I was venting to what I thought was a friend about a medical bill I had, told him I needed to pay it in order for my insurance to be reinstated, he offered to help me out with some of it, I said cool here’s the number call them up and pay what you offered to pay which was 200$, he later showed me he paid for the whole thing which was 4,000!!! I’m not in the country right now so my time is different right now so I saw it when I woke up and I wasn’t able to cancel it since it was already processed!! He was calling me lots of times the next day mind you I’m in Japan he’s in the states so time difference, I wasn’t answering so he goes and calls my family and tells them I asked to Borrow the money and I need to pay him back now!! My family isn’t wealthy so I’ve been working so hard to pay this bill slowly, but he involved my family with something I thought I was telling a friend and now he’s threatening my family that we need to pay him! How am I supposed to pay him 4000!! I don’t know what to do!! Billing wasn’t helping and said he has to dispute it on his end to cancel it and he won’t do it !!!