My name is***** am sorry to hear that you are having this issue.
I will be glad to assist you with this.
Try one of these methods please.
You can move the books from one device to another via “Manage My Kindle” on amazon.com using a web browser.
Step 1 Go to amazon.com and sign into your account.
Step 2 Select Manage My Kindle.
Step 3 Next to the Digital Content Column on the left, find the book that you want to move to the iPad and select action on the right. You can move the content from device to device there.
Solution 3: Transfer Ebooks to iPad via “Kindle” App.
Developed by Amazon,.azw is the default eBook format for Amazon devices, Kindle 3, Kindle Touch and Kindle fire. Almost all the ebooks you have bought from Amazon for Kindle are in .azw format which is not supported by iPad at all. If you need to read .azw ebooks on iPad, you should install kindle app for iPad. Only in this way, these books will be readable on iPad. To transfer these .azw kindle ebooks to ipad, all you need is log in Amazon account on Kindle for iPad and download these eBooks you have bought from Amazon in your archives.
Step 1 Download Kindle app on iPad.You can find this application in the APP Store on your iPad. Just type in “Kindle for iPad” in the APP store search box and the free “Kindle” APP will usually be the first APP that appears.
Step 2 Log in to your Amazon account.
Step 3 Sync books you have bought from Amazon to iPad.