I'm sorry to see you go, however, I want to make sure you'll be able to cancel your merchant/payments account as simple as possible.
Mobile Payments users may be able to cancel the account in the Merchant Service Center.
If you don't see this section, you can follow these steps:
A cancellation will now then be processed and will send you a confirmation letter via email within 10 business days.
For additional reference, you can check these articles:
I'm also adding this article in case you have any other payments concerns in the future: Payments FAQ.
Let me know if you have any other questions about canceling your merchant account. I'm just here to help!