Irritating calls for account that is not mine!

I have been receiving calls from an 087 number for an unpaid Thruworths account. I ignored them for the most of March until I received an sms threatening legal action for REF *** in April. Upon my visit to a Truworths store was told the account is not mine and that I should ignore the calls and delete the sms??? Right now all I want is my cell number off Truworths's database as I am sick and tired of the calls clogging my call box on top of that I do not want to receive any threatening sms or marketing material as I would go to the store if I needed anything!!!!! I do not have an account with Thruworths and never app**** for one to begin with!!!!!