Thank you for posting back. I'm happy to read that the Caller Display is back working as it should. I did check the fault first thing this morning, I could see that an engineer had been dispatched to the exchange. They managed to identify and fix a fault with the equipment in the exchange.
I gave your mobile number a quick call, I'm sorry I didn't get speaking to you. Please can you let me know if you need anything else and if you are happy for me to close the complaint on your account?