Is it necessary to break a mobile phone after breaking an oath to abandon a sin that has been repeatedly committed?

Do not break your phone due to the Prophet's (peace be upon him) prohibition of wasting money. You must offer an expiation for breaking an oath (kaffarat yamin): feeding ten poor people or clothing them. If you are unable, then fasting for three consecutive days is more cautious. You must also offer sincere repentance for this sin, seek Allah's help and supplicate Him to divert it from you and keep you steadfast, persist in the remembrance of Allah, keep the company of righteous people, constantly reflect on what benefits you in matters of religion and worldly life, and occupy yourself with good deeds.