Previous flat owner left with unpaid utility bills

Thank you GSM. I was hoping hou would pick this up!!.
Yes, I have told them this.
They have just told me, it has been going on for two years. I have told them NOT just to return the bills.

I have given them the name and address of the Solicitors who acted for the vendors when the flat was sold to them and advised them to get their own Solicitors to send letter to the Utility company and Debt collection company to stop further harrassment.

I have also told them to contact the Credit rating companies as this is likely to be listed against that flat.

Just wanted to make sure I have given correct advice.

Ringing up and speaking to the utility company is the first thing they should have done. I cannot understand why they didn't do that, Just returning mail will trigger nothing, except a note that the bill hasn't been paid.

In the meanwhile, keep handy by the front door (photographic) evidence of who they are (passport, driving licence or other official evidence), copies of their most recent utility bills, and any evidence they have that shows the date they bought/moved into the flat.

They need to speak to the utility companies and the debt collection company. Just returning bills won’t do the trick. Communication is needed. Presumably meters were read on the day the new people moved in?

Have they contacted the utility company direct? Otherwise citizens advice perhaps.