It's never easy explaining anything computer related over a phone.
I've noticed working in design that people generally underestimate the average human's ability to solve problems, even if they aren't technically literate. But any increase in the effort department would reduce the amount of returns no doubt.
Speaking from experience as we once tried to help her to connect to a open WiFi which needed an OTP-based login via the phone and gave up after about 15 frustrating minutes for all three of us!