"BMI takes 3 months to repay an overcharge for treatment!"

I had a biopsy done for skin cancer and was overcharged £93 by BMI. Not a lot you might think but it obviously was for BMI. It took them 3 months to repay me and involved 2 letters and 2 emails from my consultant, 2 emails to their Patient Query line, 2 attempted emails to their Patient Query team (these were not received as they gave me an incorrect email address) and one further email to a BMI employee. Oh, and I was told when I first contacted them about this overcharge that; the systems were down and could I contact them again in 4 days time! To top it all they, allegedly, sent a cheque to my home address which was returned to them as address unknow’. How surprising, as each of their invoices and the credit note had unerringly found their target!