Harassing me for money not owed

I keep getting sms messages from this company I am 100% convinced that they are running some kind of ****, at first I received sms regarding my Truworths account being handed over to them but the funny this I have never even spend the amount they are talking about on my Truworths acc nor do I owe any monies on my Truworths acc it is paid up in full and I phoned Truworths and they confirmed that my acc is paid in full and that they never handed me over then suddenly the same company started sending SMS messages regarding a mr price acc I have never had a mr acc in my life but the ref no on both SMS messages are the same now lately they only SMS for Truworths. I don't owe any money on any accounts and if they don't stop sending me SMS messages I will take legal action against them.