incorrect sms going out, giving other peoples details

I have been receiving sms saying im owing 7000.00 for tax no: *** When i call in they say it is for P.Govender. this is not me! i have called 4 times to have my number removed but still they are unable to sort this out. I wonder how many other people they are doing this to and giving out their names and tax numbers. Im tired over this **** now.