Is it permissible to take a phone that the father took from his brother after repairing it for him, and then asked him to sell it as if it were broken, so he gave it to him without charge?

The default assumption regarding your uncle's gift of the mobile phone to your father is that it is valid and sound. What you mentioned does not invalidate this default assumption, so there is no harm in you accepting the mobile phone. The basic principle concerning contracts between people is to consider them valid unless proven otherwise. If a contract oscillates between validity and invalidity without a clear preponderant factor, it is ruled as valid until the contrary is proven. This rule is derived from the principle that "the affairs of Muslims are presumed to be sound and correct whenever possible."