Apple sends the receipt, since Plus is billed through the App Store. We don't send separate invoices.
In your email: after each charge, Apple emails a receipt to the address on your Apple ID. Search your inbox for "Apple" and "just streak".
On your iPhone:
- Open the Settings app and tap your name at the top.
- Tap Media & Purchases, then View Account.
- Tap Purchase History and find the just streak entry.
On the web: sign in at reportaproblem.apple.com with your Apple ID to see recent purchases.
To see when Plus renews, open the Profile tab, tap Settings, and look at the Plus banner at the top. It shows your renewal date.
Need a refund instead? See Request a refund.