In South Africa, this scenario is becoming a big problem: A victim's cell phone, in their possession, is triggered to go into no-signal state which is sometimes

In South Africa, this scenario is becoming a big problem: A victim's cell phone, in their possession, is triggered to go into no-signal state which is sometimes not noticed for hours. During this time, criminals are somehow able to capture communication that would have originally gone to the cell phone. Communication like 2FA passwords. This is then used to transfer money out of the victims bank account. How can 2FA over sms be considered safe if this is possible?