Accusing me falsely of being in arrears

I received a threatening sms re an Edgars account that is in arrears, with instruction to phone a number with a reference nr. I phoned and explained that my number is incorrectly listed on their database and was assured that this will be fixed, just to receive another threatening sms today. This is totally unacceptable and I do no appreciate the threatening nature of the sms that is badly compiled.