Dd (21 but still living at home) has had falling out with close friend who irrationally decided that Dd said something out of turn 
As girls do, they each had some of each others clothes which friend asked for back. But she had also borrowed £50 off dd when she was short before pay day.
Dd has returned friend's clothes but friend seems reluctant to do same. Dd needs the money.
I told her (having kept out of it up to this point) to tell friend that if she didn't get things/money back by end of week I will tell her parents (she also lives at home).
Friend replied with 'Good luck with that it won't get you anywhere they'll just laugh at you.'
To me clearly that is not the case at all. But whole thing is getting out of hand and dd is very upset.
If situation was reversed I would want to know.