Why am I getting ANY type of message saying my data is limited due to usage or time of day when I pay handsomely for an UNLIMITED plan??? By the way, it is 8:03 p.m. EST on a Tuesday, so that rules out time of day! Given you way too much money to be dealing with this and I wish you'd never purchased ALLTEL and disgraced their brand!
Those messages normally mean that you set a data limit and / or data warning within your phones Settings. Open Settings and find the section for data usage and turn off the limit or warning and you should stop seeing those messages.