Chargent uses the Payment Request Email Workflow Rule to send the email to address entered when creating a new Payment Request. Deactivating it would cause the Payment Request to be created but no email would be sent to the person you are looking to receive it.
Since this Workflow Rule is a standard Workflow Rule in Salesforce you can either clone it to modify it or create a new one based on similar criteria.
Here is the current criteria
Send Payment Request Email Equals True and Payment Request Status is not equal to Paid
As always we highly recommend creating it in your Sandbox account and thoroughly testing it before moving it to your Production Org. This is to ensure all aspects in your Salesforce Org continue to function correctly without any errors.