iPhone calls - nobody can hear me/can't hear them. Anyone had this? :(

[dandelionwoman]

Hi all,
Sorry to ask on here but I'm totally stumped! Also feel so isolated at the mo & desperate to talk to some friends.
-Nobody can hear me/can't hear them.
-Can't use the speaker phone option - when I press it, nothing happens/doesn't change colour.
-Turned off & on about 4 times

• It's an iPhone 7!

-I'm just doing a software update... Any advice? 😱