HARRASMENT BY NIMBLE

A few weeks ago I complained about Nimble Group harassing me with phone calls, which was rectified a few days later. As soon as I gave my feedback about their services they shifted gears. Now they are sending SMSes with reference numbers. I would like to know what is stopping them from completely removing my number from their database. I cannot be 1 person using different names from different shops and besides, I DO NOT even have accounts from all the shops they are sending. One consultant told me to ignore the messages (which is totally ridiculous and unacceptable. I am now considering taking the legal route against NIMBLE.