Data speeds can be affected by many factors including terrain, weather, foliage, buildings, signal strength, high-usage periods, customer equipment and other factors. If you're still experiencing issues please reach out to our support teams via phone, chat, or social media.
As the moderator noted, there are a lot of factors that can weaken or block your phone's signal. If it happens on a regular basis, there's a strong chance you're in a weak signal area due to your proximity from the nearest cell tower. You could also have a permanent object/device interfering with the signal too. Cell signals are radio waves and these can be affected by things as mundane as high winds. First thing you should do is measure your signal (do it using this method as signal bars are inefficient indicators of signal strength). If you're consistently experiencing weak signals, you have options.