Cannot hear on phone call iphone

[Joshd1212121212]

I cannot hear on phone calls. Icon to switch between speaker and handset is greyed out. 

I'm convinced its a network issue as I took out sim card and put it back in and that fixed it but only for a couple hours. 

At the same time imessage also stopped working and will not activate aswell saying its not connected to internet. 

Any help would be aprreciated. 

Ta

[SamSam]

Do you have any bluetooth devices connected to it? Watch, headphones, speaker, etc? 

I recently got a new smart watch and one setting I didn't know was even available was to answer calls through the watch. As in, I had to speak into and try and hear from the person through my watch. Was horrible. Anyway, thought this might be happening to you without realising. 

[Joshd1212121212]

Yeah I do have a smart watch and have been having to call through it. 

How do I change settings back? 

[SamSam]

Not sure what the other guy is talking about....

What kind of smart watch do you have? I changed the settings on my smart watch itself (Samsung Galaxy) to not allow calls to come through