Square is a credit card processing company. Used them myself when I was in business. Someone must have gotten hold of your credit card number and is using it. Your bank should be issuing you a new card with a new number.
This has been reported a couple of times as a phishing scam, but I would recommend that you check your credit card receipt. My husband received a text receipt from Square for $400+ from a place called Colognes by Alex. Checked our credit card transactions and there was the fraudulent charge. Woman at the bank said that they tried 3 times to make charges to the same place; first went through and the second two were blocked.
Square is a credit card processing company. Used them myself when I was in business. Someone must have gotten hold of your credit card number and is using it. Your bank should be issuing you a new card with a new number.