problems receiving texts and voicemails

[joko]

i have a new ZTE Grand X, from Virgin, and its a nice phone and I really like it - except for one thing - the messaging.

I am getting text messages and voicemails many hours after they have been sent.
I had a few missed calls the other day at about noon and the accompanying voicemails only appeared on the handset at midnight.

texts come through hours later too - not all of them , but some

and obviously thats not good enough

it happens from all sorts of numbers an in all sorts of places, even in my own house with the wifi on, so I cant see what the problem is.

is there anything I can do? any ideas?
is there a setting or something?

in are refusing to give me a different type of phone as i have had it for longer than 14 days (about 22 days when i rang them to complain as it took me a while to realise what was happening - i thought i had 28 days as i dont remember them telling me it wa sonly 14...)
they will replace or fix it, but i am worried that its just a crap phone, rather than that i have a faulty handset.

Thanks