Network Provider Refund text

Just received a text from 'O2 UK'

"o2: Sorry, we charged you twice for your recent top up by mistake. So today, we've refunded you £10 which you will see in your account in the next few days."

I did use the lend us a quid thing but still not sure if this is genuine, anyone else had this?

Well, ask o2? If you think it is a scam text to charge you money they will soon tell you about it?

Nope, forget it just checked bank account and they changed me £20 for a £10 top up. Better not get overdrawn charge or they will be getting jarred for that too!!!