HARASSMENT BY SANBS

I am a blood donor.

have been harassed by SANBS since mid November 2021 to date. They have been sending me the same SMS (dates 25th November) to come and donate blood. I have written to them via Twitter and email to remove my number from their SMS list but it falls on dead ears. I rexieve these SMS 2 to 4 times a day sometimes as late as after 23h00

I am sick of it and I don't know what to do anymore