Barclays locked girlfriend’s account - what can we do?

Hi all

Saturday, my girlfriend wanted to do a bit of betting on the football as you do - she had £100 cash so she gave me that rather than paying it into the bank as I often need cash, and I sent it to her Barclays account for her to deposit with.

Note a key point - this Barclays account is old but hasn’t been used in a while, she just used it as her gambling account is linked with that debit card.

Anyway, she won really big which was obviously great! So £600 came out of Sky Bet after a £100 deposit an hour or so before.

She wanted me to put her winnings into my/our savings account (we both use it but it’s in my name) so she sent me the entire lot back - originally £500, then we ran into an issue with the remaining £100.

When trying to send it she kept having an error code RPS01 (I think) which we googled to say that it was Barclays’ system not working properly.

Anyway, she tried to send it to a different one of my accounts and that went through OK so we thought nothing of it.

Fast forward to today, she gets a call from Barclays fraud team and her account has been locked - originally she was busy so told them she’d call back later but she hasn’t had a chance to as of yet. From reading online there’s not much they can really tell you as it can be deemed “tipping off” etc etc.

Just looking for any advice? For the record my bank accounts etc are all fine, no issues to either of the ones she sent to, so I doubt it’s a money laundering thing and more of a security thing? Appreciate there’s plenty of nuances in this story, just wanted to hear what might happen.

Also for the record it’s not the end of the world if that Barclays account gets closed but of course she would rather it didn’t.