Help the novice, please!

Last night my audacity was working a treat, this morning I’ve come in to work and I’m getting no sound through from my phone.
I’ve tried loads of things but nothing is working.

If you’re using a USB device, plug in the device and then start Audacity, not the other way around. Audacity looks for sound device when it starts, so start it last.

If that isn’t it, then we need to find out what you’re doing … in detail. It’s super difficult to record from a telephone or a cellphone. Personal Cell Recorders will normally not record both sides of a call.