Because of urgent work, sometimes I miss Asr and combine it with Maghrib. During journey it is not possible to offer Fajr prayer so I pray it in the time of Zuhr. Sometimes 3 continuous prayers are missed and I pray them in the time of 3rd prayer. But recently I read that Asr Salat cannot be combined with Maghrib and Fajr Salat cannot be combined with any other Salat. Then is there any solution for me?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. He who travels for 83 kilometers or more is entitled to the travel permissions including combining prayers. Prayer combination is to be applied to Zuhr and Asr on one hand, and Maghrib and Isha on the other. This combination can be done either at the time of the first prayer or the second one. Fajr (dawn) prayer cannot be combined with the Isha or Zuhr prayer. Similarly, Asr prayer cannot be combined with Maghrib, or Zuhr with Fajr. There is no discrepancy among jurists on this matter. Ibn Qudamah said: Muslims unanimously agree upon the prohibition of combining Asr with Maghrib and Isha with Fajr. In al-Majmoo', Imam An-Nawawi said: It is unanimously agreed that the Fajr prayer cannot be combined with any other prayer or Maghrib with Asr. Therefore, you have to make up for the prayers performed in the wrong manner. To solve your problem, you have to pray all prayers in their due times. The time of Zuhr and Asr, while on trip, extends to the last part of the time at which Asr ends, and the time of Maghrib and Isha prayers extends to the last part of time at which Isha ends. You are not permitted to delay Fajr prayer from its due time or combine it with Zuhr. Likewise, you are not allowed to combine Asr with Maghrib or Isha with Fajr, or Zuhr with Fajr. Being busy is not an excuse for doing so, since it is very easy for everyone who has determination and resolution. It is easy for whomever Allah wills it to be so. Allah knows best.