Continuous Harassment!!!!!

This company is the worst. They continue to harass me with phone calls on a daily basis claiming that I have an outstanding CellC account. I do not have a Cellc account. I haven't had one for many years and I have repeatedly asked for proof of this account and until now I haven't received any proof. I am so sick and tired of this. If they don't stop soon I will find a way to make them stop.