Today 123RF refunded someone who bought one of my clips, five days ago. For the first time it happens to me and and I want to know how it works !?
So, someone buys a clip use it and after 5 days, realizes that it doesn't fit with his/her project and ask for a refund (for another download).

Last month I had 2 ELs refunded, total $75. Contacted 123 and they said it was a refund for a test their IT department did - last August!

That was it, end of discussion, $75 gone from my account with no real explanation.

I asked them why it was not taken out of account straight after the test had been completed - no response.

I asked them why it had taken them 11 months to take it back out - no response.

If this is genuine then I obviously should never have received it in the first place, I get that, but 11 months to rectify it and offer no explanation, apology or anything???

Not professional and not really acceptable but there is nothing I can do.

So, someone buys a clip use it and after 5 days, realizes that it doesn't fit with his/her project and ask for a refund (for another download).

Yep, that pretty much sums it up.  Personally I don't think they should give refunds for digital goods, but it is fairly common at 123 and also happens occasionally at DP and Alamy.  Never for other agencies in my experience except for iS credit card issues.  Unfortunately, like so many other agency issues there is nothing we can do about it except stop submitting.