Coin Packs are consumable purchases that cannot be restored if you reset your game. 'Remove Ads' however is a permanent purchase that can be restored. Use the following steps to restore any non-consumable purchases, like 'Remove Ads':

iOS Platform:

Navigate to the Settings Menu.
Scroll down.
Tap Restore Purchases.

Android Platform:

Purchases are automatically restored on a fresh launch with android devices. Simply confirm you are connected to the internet and then force-restart the game and wait at the home screen for at least 60 seconds. For more info check the force-restart article.

If you may encounter any issues with restoring non-consumable purchases, feel free to submit a ticket.