RIM does have a support service but to the best of my knowledge you have to pay!
They also have an online knowledgebase: BlackBerry - PDAs - BlackBerry Support at BlackBerry.com
Have you thought about upgrading your OS to the latest version? 4.5 is available from the BlackBerry software download site - though if this problem only just started happening it doesn't seem likely it's a device software issue unless you messed with the settings. Perhaps you've too many messages or something.
Otherwise seems more likely to be an Alltell issue.