you should also consider answer posted by Dr. Zakir Naik, there is no contradiction in Holy book. Problem is that you are only consulting propaganda posted by Christians, you should also consider answers that are already there.
Allah says in Quran "Indeed, your Lord is Allah , who created the
heavens and earth in six days and then established Himself above the Throne. He covers the night with the day, [another night] chasing it rapidly; and [He created] the sun, the moon, and the stars, subjected by His command. Unquestionably, His is the creation and the command; blessed is Allah , Lord of the worlds." Quran 7:54
"Indeed, your Lord is Allah , who created the
heavens and the earth in six days and then established Himself above the Throne, arranging the matter [of His creation]. There is no intercessor except after His permission. That is Allah , your Lord, so worship Him. Then will you not remember?" Quran 10:3
"And it is He who created the
heavens and the earth in six days - and His Throne had been upon water - that He might test you as to which of you is best in deed. But if you say, "Indeed, you are resurrected after death," those who disbelieve will surely say, "This is not but obvious magic." Quran 11:7
"He who created the
heavens and the earth and what is between them in six days and then established Himself above the Throne - the Most Merciful, so ask about Him one well informed." Quran 25:59
"It is Allah who created the
heavens and the earth and whatever is between them in six days; then He established Himself above the Throne. You have not besides Him any protector or any intercessor; so will you not be reminded?" Quran 32:4
from above verses, it is clear that God Almighty created this universe in 6 days. Now have a look on chapter 41:9-12
"(verse 9) Say: Is it that ye Deny Him (Allah) Who created the earth in two days? And do ye join equals with Him? He is the Lord of (all) the worlds. (verse 10) He set on the (earth) mountains standing firm, high above it, and bestowed blessings on the earth, and measured therein all things to give them nourishment in due proportion, in four days, in accordance with (the needs of) those who seek (sustenance). (verse 11) Moreover, He Comprehended in His design the sky, and it had been (as) smoke: He said to it and to the earth: 'Come ye together, Willingly or unwillingly.' They said: 'We do come (together), in willing obedience.' (verse 12) So He completed them as seven firmaments in two days and He assigned to each heaven its duty and command. And We (Allah) adorned the lower heaven with lights, and (provided it) with guard. Such is the Decree of (Him) The Exalted in Might, Full of Knowledge."
The Muslim Scholars have reconciled between the verses of Surah Fussilat (which imply that the heavens and earth were created in eight days). The four days mentioned in verse 10 include the two days in verse 9. Thus, the two days in verse 9 refer to Sunday and Monday and the four days in verse10 refer to Tuesday and Wednesday (including Sunday and Monday). In verse12, Allah mentions that He complete the heavens in 2 days. These 2 days were Thursday and Friday taking the count to six days. (Tafseer ibn Kathir vol.4 pg.83; Darul Mufeed Tafsir Jalaalayn pg.397)
