Trying to make a phone call and keep getting the message 'this phone number is not recognised', for two numbers. I know the phone numbers are fine as I've had someone else try it. I think the problem is that when I ring it, a message comes up saying 'HD calling' (high definition??. ) This is the first time I've noticed this. I've been online to try find out how to turn it off but can't work it out. The weird thing is, it only happens with these particular numbers, both for the same company.
Can anyone tell me how to turn this off and why it's only happening with this one company? One of their numbers is a regular landline and one is an 0800.