Uninstallation Instructions for OpenCart 2.x
Before you begin We recommend you do a full backup of your OpenCart files and database, just in case.
If you correctly follow these instructions, no damage will be done to your OpenCart system.
Navigate to Extensions > Payments and click Uninstall for the extension Square. This removes all extension settings and events, and drops the following database tables: squareup_customer, squareup_transaction, squareup_token meaning all information about stored transactions and saved cards will be lost.
That's all! If you did not like the Square extension for OpenCart, we would love to hear your feedback so we can make it better. Feel free to leave your comments on firstname.lastname@example.org