can a person get fired for playing on the phone

Unless you have a contract  (which could be a union contract or, sometimes, an employee manual) for a required duration (i.e. a 2 year employment agreement) or one which limits the reasons for which you can be fired (e.g. "employee can only be terminated for ... ), or unless you believe you were fired for reasons which are unlawful by statute (e.g. for race, sex, age, religion, etc.), you can be fired at any time, for any reason.