Tax refund to a third psrty

I received a letter from HMRC advising they had sent a cheque to NATIONWIDE PPI ADVICELTD I did not authorise them to claim the tax refund. I then received a cheque which I paid into the bank however it was declined as fraudulent. I have tried to call the company J cannot speak to anyone. I have emailed them and got no reply. How do I get my money from HMRC?

Hi,
If a fraudulent claim has been submitted on your behalf  then you would need to report the details to action fraud 0300 123 2040 website:
Action Fraud
Thank you.