I am currently dealing with this situation, this morning I processed a refund for 7.30 to the buyer as I was able to combine items and wished to remiburse, when I got home this afternoon paypal had reversed pending withdrawl transactions to my account to cover the refund which was for the total transaction amount of 87.30 not just the 7.30 I entered to be refunded

I have contacted paypal and am awaiting a reply however I also contacted the buyer who is also a seller and they are only to happy to send the payment to me again if I cannot have the pending refund transaction cancelled by paypal

I am thankful my buyer was so understanding however in future I think I shall always use the send money option rather than risk processing partial refunds