Unable to connect to other sky mobile users

[Pitbull01]

Hi, for some time now on and off I am unable to contact other family members that have a sky mobile account. It goes to dial then after 5 seconds it cuts off. It does this with giff gaff and other operators sporadically.  I have phoned sky previously and they said there are no faults. I've switched on/off rebooted and that dosent do anything.  It is frustrating as I have to text them and ask them to ring me, this has been happening for months.  Any ideas? 

[caesarome]

@Pitbull01 

It might be worth contacting them and asking them to send you a replacement sim to activate and try to see if it then works for you.

[Pitbull01]

Good idea thanks, they never gave that to me as an option when I rang them when it first started. They said it was my phone as I have an huawei? Which I thought was strange as didn't have problems when I was on 02, but you give up if your not tecy enough and they keep saying nothing wrong with signal etc.