My Mom Vs. the Cell Phone

Me: Hi, Mom? i just sent you an e-mail.
Mom: What? I can't hear you!
Me (louder): Mom? I just sent you ...
Mom: I can't hear you!
Me (almost yelling): I JUST SENT ...
Mom: WHAT ARE YOU SAYING? I CAN'T HEAR ...
(breaking up, Kate hangs up and calls back on niece's phone)
Me: Hi, A____? Let me talk to Mom.
(Mom is laughing in the background)
Me: Hi, Mom, I sent ...
Mom (still laughing): Amber just must have a better whatchamacallit than I do!
Me: Yeah, so, I sent this e-mail ...
Mom: What?