Before filing a dispute claim:

• Review your transaction activity to see if you've had charges from the company before. 
• Confirm the transaction is truly unauthorized or incorrect. For example, if someone else has access to use your account, consider asking them about the activity and review any receipts received. 
• Try to resolve the problem with the merchant directly. It can help resolve the dispute quicker. If you do file a claim, the process can take up to 90 days to resolve.
  See also: How long does it take for my credit or debit card dispute or fraud claim to be resolved? 
  See also: Do I need to contact the merchant before filing a credit or debit card dispute? 

If you're sure the transaction should be disputed, be sure to file a claim within 60 days from the statement's date in which the transaction appears on. Then, gather all the evidence you have like receipts, order confirmations, emails, screen shots, etc. 

Through the dispute process, we'll ask questions about your experience, what was expected vs. what was received, etc.
See also: What can I expect when I file a credit or debit card dispute or fraud claim?