I bought the Player's Handbook and my account got charged, but I can't download it. Instead, the app shows that I still need to purchase it. I have a receipt email as well as proof of purchase. Is there a way to get my book to download? :P

You can't download the digital book on your PC. You can view it here: https://www.dndbeyond.com/sources/phb

I downloaded it on my tablet and it still says I need to buy it to read it. :/

What do you mean "my account got changed"? Purchases are tied to your account and cannot be migrated under normal circumstances. If you log in with your purchasing account, the books should be there to view, not download

I meant my bank account. When I select the book, it takes me to the purchase page on the app. I can't view the contents of the book at all.

Ok, you need to check if somehow you got two different DDB accounts, one logged in the mobile app, one for the website.

Purchases between the two platforms do sync on the same account.

I checked and it's the same account on all devices. I'm not attempting to access the book on the website though, just on the tablet. Although even with the link provided above, it redirects me to buying the book.

I had this as well, purchasing a source book within the app will not allow you to download it, until you stop the app in memory, restart it and then tap on download. Seems to be a caching problem.

Then, this problem must be forwarded to support, with all the details: https://dndbeyond.zendesk.com/hc/en-us/requests/new?ticket_form_id=602788

Will do! Thanks for the help :)