not sure where you stand but i had a simular problem a few years back over £40 for bits i never received and disputed it with pay pal and they agreed with me and credited me with £17 from his account (which was the total amount of money he had in his acount) but because thats all he had that all i could have back.

obviously i wasnt happy but after the amount of stress etc it caused i just let it go and moved on.
a few months later a random £23 was put into my account, turns out as soon as the seller had some money put into his account paypal instantly took the money he owed me and put it im my account.
good luck getting it sorted, it can be a long process but all the best