I've had a lg rumor touch from virgin mobile for about two years now. When I first got it everything was fine but recently incoming texts messages I wouldn't get until 20 mins after they were sent, or when I was sending a text it would say there was an error and I would have to turn it off then turn it back on to get it to work. I think turning it on and off too much makes it work because last night I was texting and I just all of a sudden stopped getting texts. At first I thought it was the person I was texting being slow but I tried sending a message and it wouldn't let me. I got my friend to send me a message last night an i still haven't got it. I turned the phone on and off again, I even pulled the battery out and put that back in but i still can receive or sen messages. I don't know of its my phone being stupid or if it's the whole virgin mobile system.
I have the same phone and the same service. I HATE VIRGIN MOBILE!! The phone is crap, I've had mine for a year never dropped it and it will turn off on its own, I have the same problems with the texting, the touch screen will just stop working and it will just randomly freeze. My siblings have different phones by virgin mobile and they seem to only have issues when trying to call tech support. (I wouldn't advice calling if you don't have to but if you do keeping asking for the person's supervisor so you can someone who speaks and understands English) I believe that the problems you are having are related to the piece of crap phone not to the service.
It sounds like the cellular service but it could be your phone, I would call customer service