[Margaret Pilkington]

Not had any letters or anything like that.
I think my action would be to check that they had not taken any money from a bank account and once this was ascertained I would then be contacting the company to find out what was going on.
This looks like a company that protects other organisations from breaching the Data protection regulation...and it seems unrealistic for your Mum to have any contact with them.

If money has been taken from her account...then how did the company obtain her account details?

It needs to be looked into.