0800 number 'call failed'

[tdr012]

I've been waiting for phone calls off an 0800 number, when the number rings me, it rings through but when I answer the call it immediately switches to 'call failed'. When I ring them back, it connects and allows me to make the call but every time it gets to around 50 seconds in, it either switches to 'call failed' or the line goes completely silent. 

I have contacted o2 and they've said there is nothing on my account causing these issues and I've checked all of my iphone settings and nothing is showing that should be causing this. Its extremely frustrating!

Does anybody have any advice on what else I can do? I haven't got another phone at home to try my sim card in and my phone is brand new so I shouldn't be having any problems with it. 

[MI5]

@tdr012 

Try a different 0800 number and see if it's the same problem.

[tdr012]

Just tried another 0800 number and that got 8 seconds in and failed. 

[MI5]

@tdr012 

Possibly a sim card issue then.

Pop in store with photo ID for a replacement. Also ask them to double check everything on your phone and account.

If phone is suspected, seek help from the manufacturer in the first instance.