If your phone is displaying "no service", is there a SIM card in the phone, are you inside a building or away from a communication cellular tower?
Next thing to try would be to backup any or all information to a personal or laptop computer and do a factory reset on the phone. After completing the factory reset and that doesn't solve the issue then the final steps would be to try a software update using the "settings" app installed on the phone. If no updates are available then bring the phone to a TELUS Store, ask the store associate to lend you a loaner phone and have your current phone sent out for repair. Best Of Luck getting these issues solved!!!!