The Only way to cancel a purchase made through TurboTax is to contact TurboTax support and speak with a TurboTax agent. They are the only ones who can cancel the purchase. No one in this forum has access to your TurboTax account.
If you have already purchased the software from TurboTax you may be able to request a refund.
Go to this TurboTax website to request a refund for the software purchased from TurboTax - https://support.turbotax.intuit.com/forms/refund-request.jsp
Use this TurboTax website to check your orders and payments -
https://turbotax.intuit.com/personal-taxes/cd-download/order-status/
