No dial tone, crackling noises on landline

My landline stopped working yesterday, it just crackles and has no dial tone. 

I've tried 2 different handsets in all sockets and they are all the same. 

I've tried using the test socket in the main wall mounted box and it's the same. 

I've checked in my hub 4 router and telephony hasn't been enabled (I've had no notification that it has been but thought I'd check that after reading other threads).

What's the best way to contact support, I thought I'd previously done it via WhatsApp but I can't find that option.