I started having this issue about two months ago, where I would be having a text conversation with a friend, and then I would stop getting responses.
Later, I found out that he had been sending me replies but I wasn't receiving them. Lo and behold, at four in the morning the next day, I received about 30+ text messages that had been sent to me throughout the previous day.
Called customer service and all they did was tell me to text myself (which I did and got the text), and then they refreshed my signal.
But that didn't fix my problem.
Upgraded my phone to 2.2 and that seemed to fix the issue. I had no problems receiving text messages when they were sent and no more delayed messages. Until two days ago, I received everything on time. But then, I started to not receive the messages until some random time hours later (usually in the early morning hours).
Is there any way to fix this? My main method of communication for work is by text messaging but if I don't receive them until hours after the fact, pretty much, I'm screwed.