Recover Hacked Pokémon GO Account

I'm seeking an experienced individual to help me recover my Pokémon GO account that I believe has been hacked.

Here are the key details:
- The email, username, and other details have been changed by the hacker.
- I can still provide my trainer code.
- I have proof of ownership in the form of purchase receipts and friends who can confirm the account is mine.

Ideal skills and experience:
- Experience with account recovery, especially for gaming or high-security accounts.
- Knowledge of Niantic's (the game's developer) account recovery process.
- Ability to provide guidance or execute steps to regain access.
- Strong communication skills to keep me updated throughout the process.