The phone after a while will display the "No Service" icon. I will either have to restart or reboot the phone once or several times to get it to work again. I've tried using my other Rogers sim card, a Hong Kong PCCW and a China Mobile sim, but I still have the same problem.
I did a search on the internet, some people have the same issue as I do but there was no fix for this problem.
The phone is a unlocked Rogers Captivate running the stock Froyo Rom.