Thank you for your reply, for trying that suggestion, and for sharing your experience.
As Apple customers, just like you, we have no access to your accounts or details, so there's only so much we can do to help.
You might want to find the URL (internet link) of the app offer,
Find the URL for content to report a concern - Apple Support
and
then "Report a Problem" to Apple:
https://reportaproblem.apple.com/?s=6
Else: Apple's Subscription and Billing Team may have suggestions:
There's a "Still need help -start now" link at the bottom of their webpage
(online chat / phone / email etc,)
Subscriptions and Billing - Official Apple Support
All the best :-)