Computech ******** numerous people

I have recieved numerous sms and mails now saying that I owe them money. Everytime I ask them please forward me the proof or signed contract no response. And then I get an sms again. I have never made use of them or even know what they do. Is there anyone that know how to handle this or what legal steps can be taken. I have seen that there has been numerous complains on hello peter about the same issue with this company.