Has anyone taken on abbey with the bank charges?

yes they robbed my brother of 170 quid in illegal charges.we sent in a letter demanding they return it or we would persue legal action.they ped in onto customer services and now 4 weeks later they replied saying it would take them another 4 weeks to investigate it thoroughly.its just disgraceful stalling tactics, what a way to treat your customers what a ****** shitty bank they are