Unbelievable Inefficiency

I have no idea who this company is but I suddenly started receiving sms's regarding non payment. I emailed them as I've never heard of them or had any dealings with them. They said I must ignore the sms. No explanation, nothing!!! I continue to receive sms's which threaten to blacklist me, ENOUGH IS ENOUGH. STOP SENDING ME THIS NONSENSE AS I HAVE NO ACCOUNT WITH YOU!!!!!!