Unacceptable issue again standard bank

I live in the middle of Kruger national park and I have absolutely no mtn cell phone signal. (I had to change to mtn recently, from vodacom..) Which means I can't transfer money and I am the sole bread winner in my family. Standbank refuses to let me Change my OTP to email instead of sms unless I go to the bank. I can't make any transfers or pay any of my accounts!!(THE FIRST TIME I CALLED STANDARD BANK MR PERCY SAID IT WAS TOTALLY POSSIBLE) How is this possible? I work six weeks cycles and I physically can not get to another standard bank in the next 6 weeks. This is a huge issue for me as I desperately need to send money home to my family. Iv been with standard bank my whole life but this is ridiculous and this is not the first time Iv had an issue. Last year I had literally 4 brand new standard bank cards that literally would not work. My boyfriend is FNB and he changed his OTP to email instead of sms when he moved here too. I really cannot cope like this.