Dont want an account

I was cornered by one of their 'agents' to see if i qualify to open an account. After half an hour of explaining to this person that i have no interest in opening an account, and that i dont actually shop at ackermans, just looking for something, he assured me that he will just check and thats it. Well, its been almost a year, and i have received sms's EVERYDAY, for me to open an account. I dont know how to stop it. These msgs are irritating me to the core, as i use this number for my small business. I keep blocking them, but tomorrow will just be another number. How can i make them stop harassing me