Voicemail Notification

[Jettgear]

Hello. Forgive me If this question has been asked before, i just couldn't seem to find it (if any) Here's my problem.

I have an iPhone 3G Jailbroken, i decided to get rid of my iPhone data plan and replaced it with the regular AT&T plan. I am aware that after doing that, my visual voicemail will not work anymore and that's fine by me. I am able to receive voicemail but the problem is that I do not get notified If someone had left me a voicemail. It doesn't give any voicemail icon like the way it used to do when I had the visual voicemail. I tried putting my sim card to a couple of regular cellphone (Nokia & Sony Ericsson)and i was able to get voicemail notifications on those two regular cellphones.

Is there a way to fix that? All help will be greatly appreciated. Thank you!