As per the official website of ICAI, the foundation course student will get 1 coupon and the Final course students will be allowed 2 coupons. So if you have not used your coupon you can use it and there are no restriction regarding reordering of books.

TO know about more FAQ's you can visit the link provided below:

https://icai-cds.org/faq.jsp

I hope this answer helps. All the very best for your future endeavors!