Builders warehouse spam

After numerous calls and in store visits i still get flooded with spams sms's. I have never contacted builders warehouse at any time to ask for a call back. Then just out of nowhere i started getting sms's. Not 1 at a time back 7, 8 in succession. Sometime 3 times a day. You can block the numbers but it just won't stop. I called them nothing gets done. I go in store and get the staff to call them. Nothing gets done. The spam just will not stop. I have about 300 sms's and co7nting. How do you get it to stop. Anytime day or nighy iy just don't stop.