Tafsir of Al-An'am 6:49

(And those who denied Our signs) i.e., those which the messengers, peace be upon them, conveyed during [the time of] giving glad tidings and warnings. It is also said: What is meant by them is our Prophet, may Allah bless him and grant him peace, and his miracles. The former is the most apparent interpretation. The relative pronoun [Al-ladhina] is the subject, and His saying, exalted be He, (the punishment will touch them) is its predicate. The sentence is conjoined to [the verse] "(whoever believes)..." and so on. The intended punishment is the punishment they were warned of, whether sooner or later, or the essence of punishment and its genus, which encompasses that in a primary way.

In describing it as "touching" (mass), there is an indication that it is placed in the position of a living being that acts as it wills; thus, there is a metaphorical allusion (isti'arah makniyyah) in it, according to some. Al-Tayyibi allowed that the "touching" be a consequential metaphor (isti'arah tab'iyyah), without there being a metaphor in the "punishment" itself. What is apparent is that what has been mentioned is based on the idea that "touching" is a characteristic of living beings. In al-Bahr, it is stated that it implies volition, though some have rejected this. 'Isam al-Millah claimed that the "touching" points to the fact that the punishment does not seize them in such a way as to annihilate them, so that they might find relief through death, and this has its own merit.

(Because of what they used to commit of disobedience [fisq]) i.e., because of their fisq.

Yes, Ibn Jarir recorded from Ibn Zayd that every fisq in the Qur'an means "denial/lying." This is likely debatable, as [the term rather refers to] their continuous exit from the fold of faith and obedience. It is sometimes said that a fasiq is one who departs from the commitment to some of the rulings, but that is not appropriate here.