Unable to send SMS

[Clobo21uk]

Hi, 

I was late paying my bill and I was cut off, since being connected again (paid my bill and been connected again for 2 days) I have been unable to send SMS messages to anyone. I get the red exclamation mark and an option to try again but it doesn’t work. 
I spoke to someone on live chat but he told me to go to Apple and pay for a repair as my phone is obviously broken but I’m 100% sure it’s nothing to do with my phone being broken. 

I’ve checked all my settings, everything is on, I can make & receive calls, send and receive iMessage and use my data, I just can’t send SMS (I can receive them from three but I think I’ve missed them from other people). 

[PeteG]

Hello there.

That's really quite strange. If you're still having the issue, could you try resetting the network settings on your phone? If that doesn't work, do you have another phone handy that you could test you SIM in? 

Pete.