A private key is a string of random hexadecimals (numbers 0 to 9 and letters A to F) that looks quite similar to a normal wallet address. This is created concurrently with a wallet address' creation and is usually given to you by your wallet service provider when you create a wallet address. However, depending on the wallet interface that you are using, you may or may not be given access to the address' private key (please refer to your wallet service provider for more information on this).

However, it is always best to contact the contract's deployer or team members for further assistance or a definitive solution for the issue as they are more knowledgeable in this subject matter and are in a better position to assist you.