I didn’t order this 69.99 app

Start here: https://support.apple.com/en-us/HT201382

And here too: https://support.apple.com/en-us/HT204084

you can use the contact support link at the top of the page to contact Apple directly.

Who’s telling you this? Have you checked your purchase history? Have you checked your bank account? If you’re just relying on some email there’s every chance it’s a scam designed to trick you into disclosing your account password.

It’s quite hard to buy an app without even knowing it.