I have an Umi Max and am using the prepaid unlimited messaging plan. Fairly frequently I encounter an issue where all SMS messages fail to send. I go to school in London, Ontario, but am originally from Barrie. Last year and throughout the summer (where I was in both London and Barrie) I had zero issues with my phone, but last week when I returned to London I was having tons of issues with SMS failure. The problem doesn't happen all the time, but comes rather in spurts- an hour or two (or four) where I simply can't send messages. This is rather annoying as SMS is my main way of communicating with most people. This never happened in Barrie, nor did it happen when I was living in a different location in London last year. I have tried all of the obvious things: ensuring the cell radio is on, restarting the phone, removing and reinserting the sim card, even performing a factory reset. Any ideas what I should try next?