Authorisation Failed: BB Pearl 9105

[Binkle70]

Can anyone help please before I lose my marbles totally?

3mths ago, I purchased a BB Pearl from eBay (unwanted upgrade). It was brand new, all parts still in original plastic packaging and sealed etc. It worked fine with a vodafone contract sim for 2mths. Then, took the sim out and wiped personal info off mobile and passed it to a friend. She got herself a sim on contract with vodafone and took over the mobile. It wouldn't make or receive calls/txts.

I have since took the mobile back and put the original sim back in, and the same problem. When I begin a call, it says "Call Forwarding Conditional" then "Authorisation Failed".

I have checked all the settings, radio is on etc and mobile network is ticked and appears to be working. Good signal, says Vodafone Uk across the top. I have checked with Vodafone literally about 7 times now, and they have confirmed (even via email) that it's definitely not reported stolen, blacklisted or barred. They can't work out why it doesn't work.

A techy friend has wiped all the OS and software off it and reinstalled it. He says the antena is working, the OS is working they handset seems to be working fine... but we can't get it to make the calls.

I have even unlocked it to use with any network, and the same thing happens, signal, network logo, etc and "Authorisation Failed" when you try to call.

Vodafone helpdesk exhausted their knowledge (after about 2 mins if truth be known) and I can't get any further.

Help please?