Hi, not sure if this is the correct place to post or not but.....

Just bought a parallel imported Z1 Compact online ( reputable dealer in AK ) and it doesn't appear to want to connect to the Spark network with my Sim. Well I say does not but it has a couple times and then the network drops off again. Have sent a text, made a phone call but then it drops off again. Sim worked fine in my old Z1 ( before the screen cracked ) and in the Motorola Defy I used in the interim. 

It doesn't appear to be locked as it found the Spark network a few times, Skinny, Vodafone and 2 Degrees also. Checked the IMEI number out, all fine. Factory rest made no difference. Am I missing something blatantly obvious here? 

Searching for network operators turns up 2 Degrees in 2G and 3G as well as VF 3G, sometimes Telecom(?) and very occasionally Spark. But never long enough to be reliable. I have tried all modes for searching for networks, but Spark popped up on WCDMA preferred which is correct I think? 

Before I send it back is there something else I can do?

Cheers
Chris