All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.
There is no harm in buying the Mus-haf (copy of the Quran) or books on Islamic knowledge online and ordering that they be delivered to your house.
However, if it is known or predominantly thought that buying in this way exposes the Quran and books on Islamic knowledge to be touched by the non-Muslims or carried by them, then it seems that this is forbidden.
The Prophet forbade traveling with the Quran to the land of the enemy lest it falls into their hands.
‘Abdullah ibn ‘Umar, may Allah be pleased with him, narrated that "the Messenger of Allah forbade traveling with the Quran to the land of the enemy." [Al-Bukhaari]
The Kuwaiti Fiqh Encyclopedia reads, "A non-Muslim is forbidden from working in printing the Quran. Al-Qalyoobi said, 'A non-Muslim is forbidden from binding the Quran and gilding it.' However, Al-Buhooti said, 'It is permissible for a non-Muslim to make copies of the Mus-haf without touching or carrying it.'”
Allah knows best.