Your online statement is showing authorizations, not actual charges. When you click more than once on "Submit" to send in your order, the online order processing system may send more than one request to your credit card company for payment. Each authorization is available for MakeMusic, Inc. to charge, but we only have a single order placed. When your order ships, your card will be charged a single time for the appropriate amount.
Your bank has its own rules as to how and when unused authorizations are removed. If you receive a paper statement showing multiple charges from MakeMusic, Inc., please contact Customer Success here and we will work with you to resolve the duplicate charges.