CHARGED BY A COMPANY I HAVE NOT DEALT WITH OR BEEN INVOICED BY

I keep receiving threatening SMSs from Turdon stating that our Yellow Pages account balance is in arrears and that imminent legal action will be taken. We have not had an advert in the yellow pages and cannot imagine how we could then be billed by this company. I have no dealings with this company at all and have never received an invoice from them, only threatening messages. I have called the number listed in messages but no answer or the call cuts. Any advise on how I can address this?