I know exactly wat you mean! I have it all the time!!! I had a customer who I was trying to help, who didn’t know how to open a web browser!!! (This is someone who works in an office!!!!!!!!!) I dunno how she got her job and how she keeps it!
How to deal with it? P-A-T-I-E-N-C-E!! (and of course keep muting the phone to let out a giggle!)