Hi callista32,
There seem to be two issues here. One is your email not receiving the invoice. I suggest you check you spam folder.
Even though you did not receive the invoice, you can still cancel the subscription and request a refund without the original invoice. Read what I wrote here:
You must first cancel any subscription automatic renewal (if you simply delete an app this does not cancel subscriptions):
Review the information in this support article by clicking on the link to learn "How to cancel a subscription from Apple." - https://support.apple.com/HT202039
- "If you signed up for a free or discounted trial subscription and you don't want to renew it, cancel it at least 24 hours before the trial ends."
- An existing subscription will normally continue until the end of its term and then just not renew. Stopping automatic renewal is effectively canceling it.
- Canceling a subscription does not automatically start a refund. If you want to do that:
Click on this link to "Report A Problem" and ask for a refund. --> https://reportaproblem.apple.com/?s=6
If Report A Problem does not work for a subscription refund you may have to make a special request. Click here --> https://getsupport.apple.com/?caller=kbase&PGF=PGF51002&category_id=SC0060&symptom_id=23330
Apple's terms of purchase in the USA are, "All Transactions are final" (https://www.apple.com/legal/internet-services/itunes/us/terms.html ), but some countries have different laws so check terms for your country at: https://www.apple.com/legal/internet-services/itunes/. If sales are final then it is Apple's decision if they want to grant a refund. You can always ask, and people do get refunds on a case by case basis, but Apple can also say no.