Helo all

I recently sold a phone on fb marketplace. Phone was reset and screen was working fine (as i had gone through the phone after the reset to set it up for the buyer).

Met up with the buyer and handed the buyer the phone to check (even told buyer to check while i wait) and after a couple of minutes, buyer hands me the cash.

About 2 hours later, buyer messages me on fb and says something wrong with the screen. I asked can you tell me exactly what the problem is? No answer until

next evening. Buyer says took phone to a phone repair shop and guy at the repair shop told buyer that phone had motherboard problems. Buyer then gets angry (sends me angry messages)

to get a refund, threatens to call the police on me etc. I felt pretty bad but at the same time its an older iphone and i sold it for cheap so i offered buyer to pay half of the repair costs

as long as i get the receipt because i did not want to meet up with buyer again (due to the buyer's aggressive nature) nor did i want the phone back (as it was already probably

fiddled with by the repair guys) and condition of phone is unknown. Buyer was acceptable to my offer to pay half of the repair cost that night (2nd night). Next day, i get a message

from the buyer saying the phone is not repairable and wants a full refund (3rd day). I say i am not going to refund in full but i am somewhat agreeable to bank in some money to the buyer's 

account (as i had already promised the buyer to pay half of the repair cost). After some back and forths, buyer was still angry and said will take this matter to the police.

My dilemma is i do not want any trouble with the police. I am not a phone expert and it could well be that the phone has motherboard issues being an older iphone 10, although the screen was working fine when i gave the buyer the phone.

Not sure on my obligations here. Any comments?