HTC Touch Diamond can't connect to Vodafone emailplus

I recently bought a HTC touch diamond (I know old model but had a lot of Pocket PC software from old Axim which it replaced) running windows mobile 6.1 and set up Vodafones emailplus which worked fine for first few weeks.

Now it won't connect

I have uninstalled and reinstalled a few times but no joy.... (can't connect to intiate setup)

Called Vodafone a few times who, apart from doin the above and checking I was set up there end, are now saying it's a hardware problem and because phone wasn't supplied by them they can do no more

I don't think it's a hardware problem... reckon it's a windows setting on my phone

I'd be very greatful if anyone had a fix for this as having push email was one of the reasons for geting the phone