If you were mazoor [excused person] or ill or you were in such a place where the conditions of Jumuah were missing and you offered Zuhr salah instead, then you shall get no sin. And if the conditions that make Jumuah wajib were found and yet you missed Jumuah out of laziness and carelessness, then you committed severe sin and doing so for three Jumuah continuously increases the severity of the sin. And there is no other way to get rid of it except of taubah and istighfar. You should repent wholeheartedly your sins and seek forgiveness of Allah. Also, make firm intention that you will not commit this sin in future. Also if you have not offered Zuhr salah then make its qaza. It is mentioned in a hadith that a person who missed three Jumuah consecutively due to laziness (without a Shariah excuse) Almighty Allah puts a seal on his heart. (Mishkah) Another hadith says that people should not miss Jumuah salah otherwise Almighty Allah shall put seal over their hearts and they would be among the heedless (i.e. they shall be deprived of taufiq for good deeds) (Mishkah).
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband