Neglecting Fasting in Ramadan

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Any Muslim who neglects fasting in Ramadhan, without a reason accepted by the Shari'a, commits a major sin and should first repent to Allah because he has violated Ramadhan which is a pillar of Islam.
Narrated Abu Dawood, Al Tirmizi and Ibn Majah from Abu Huraira that the Prophet said: "Whoever leaves fasting a day in Ramadhan without an excuse, that Allah has set out for him, will not be able to make up for it even if he fasts for the whole eternity. "
Imam Al Dhahbi said: "It is established among all Muslims that whoever gives up fasting in Ramadhan, without a legal excuse such as an illness or a travel, is worse than the alcoholic, the adulterer and the fornicator. They even doubt his true belief and suspect him of infidelity and decadence. Moreover, he should make up for any days he missed to fast. The evidence for this is the order given by the Prophet to the man who had sexual intercourse with his wife in the day of Ramadhan. He ordered him saying: "Fast a day instead of it" (Abu Dawood and Ibn Majah).
So since it is obligatory on sick people and travelers, who are legally excused, to make up for the days they missed to fast, it is at least obligatory on those who did not fast although they were fit and not traveling, to make up for the days they neglected to fast. On the other hand, one is not obliged to make up for the days he missed on a consecutive basis unless the number of days he is supposed to fast and the number of days remaining before the coming Ramadhan are the same. In this situation one must fast successive days for the Hadeeth narrated by Aisha she said:" Sometimes I missed some days of Ramadan, but could not fast in lieu of them except in the month of Sha'ban." Said Yahya, a sub-narrator, "She used to be busy serving the Prophet." Albukhari "Delaying to make up for the missing days without a legal reason until the coming Ramadhan is not allowed. But if one happens to do so he should then make up for the missed days and feed a Miskeen 'poor' for each missed day as an expiation. This is narrated from Ibn Omar, Ibn Abbass and Abu Huraira.
In addition, if one has sexual intercourse during daytime in Ramadhan he should make an expiation for that as described below: Freeing a slave exempt from defects, if he can not do so he should fast two consecutive months. If he can not do so he should feed sixty poor/needy people as narrated by Abu Huraira in the following Hadeeth: "A man came to Allah's Apostle and said, "I am ruined." The Prophet asked, "What do you mean?" He said, "I had a sexual intercourse with my wife during Ramadan (while fasting)." The Prophet asked him, "Can you manumit a slave?" He replied in the negative. He then asked him, "Can you fast for two successive months continuously" He replied in the negative. The Prophet then asked him, "Can you feed sixty poor persons?" He replied in the negative. In the meantime an Ansari came with a basket full of dates. The Prophet said to the man, "Take it and give it in charity (as an expiation of your sin)." The man said "Should I give it to some people who are poorer than we O Allah's Apostle? By Him Who has sent you with the truth, there is no family between Medina's two mountains poorer than we." Allah's Apostle told him to take it and provide his family with it.
Allah knows best.