How to cancel your Intuit Merchant Credit Card Services account
Mobile Payments users may be able to cancel online here in the merchant service center. Choose Account > Account Profile and scroll to the bottom of the page to the Account Cancelation section. If you don’t see this section, follow the steps in this topic. Also, Mobile Payments offers pay-as-you-go accounts. To see if you can switch your account and learn more, call us at (800) 877-3279.

If you want to cancel your account and you have processed transactions in the past 90 days, please call us at 800 877-3279.

If you want to cancel your account and you have not processed transactions in the past 90 days:

Submit your cancelation request in writing. The following information is required:
Business name
Account number
Reason for closing
Signature of the individual who opened the account
Fax or mail your cancelation request to:
Fax: 866 390-0010
Mail: QuickBooks Payments
Attn: Customer Retention
21215 Burbank Blvd.
Woodland Hills, CA 91367

We’ll process the cancelation and send you a confirmation letter via email within 10 business days.
Need to reactivate your account? You may reactivate your existing account within 6 months simply by calling us at 800 877-3279.

SOURCE LINK: https://merchantcenter.intuit.com/wapweblet/ims-mp-help/en/pos/svc_mp_cancel_account.html