8820 problems on T-mobile & Virgin.

Hello. i have been having problems for over a week now. with my 8820.
I bought it second hand as seller upgraded, he showed me it all working and it was fine.
i got a virgin payg sim credited the sim and text month to number i forgot now. never recived a reply text. i contacted virgin tech and they took me through a few steps to set it up he managed to get GPRS to apppear in caps on my phone done host routing table. and said he will check to see if its gone through which it did i had to reeboot. he said he was going away to lunch and would ring back. by which time phone should be running and recive a text. No text and no call back. left it till 4pm i called them. someone else said he will look in to it and call me the next day but pull my battery every hour. (did that) following day no phone call and gprs is now lower case. called them and they said it was to do with T-mobile and they couldent tell me a day it would be sorted.
With that i thought i'll go straight to T-mobile bought a sim and booster pack nothing contacted T-mobile tech they said they set it all up for 6 months do host routing wait for text. nothing. asked me for the firmware version of my phone soon as i told them it was v4.5.0.174 they said i need to update to v5 or above for it to work ???.
so now i'm stuck as there is no compatible one for my 8820. surely that wouldent be a problem otherwise there would be a new version for the phone.
any help or advice would be most gratefull.
Thank you.
Sean.:confused: