Why am I paying a fee over money that I got refunded?

[Elly74]

I received a refund from a person, when I went to check I had to pay a fee of $4 something for money that I was refunded for.

How is it even possible that I have to pay a fee on receiving money back?

[kernowlass]

@Elly74 

Then they didn't use the 'refund' option but the 'send money' option and sent it as a goods/services payment?