Ummy ≠ Illiterate

وَإِن تُطِعْ أَكْثَرَ مَن فِى ٱلْأَرْضِ يُضِلُّوكَ عَن سَبِيلِ ٱللَّهِ إِن يَتَّبِعُونَ إِلَّا ٱلظَّنَّ وَإِنْ هُمْ إِلَّا يَخْرُصُونَ

For a complete refutation regarding the claim that the prophet was illiterate, check out the following article.