---
updatedAt: 2025-06-04T21:35:26.000Z
agentTools:
  projectIndex: https://documentation.paysimple.com/llms.txt
---

# Collect Payment for Existing Customer

### 1. Retrieve the PaySimple Customer Id stored in your system.  If you don't have customer ids stored yet, you can call [list customers](https://documentation.paysimple.com/reference/list-customers).

### 2a. If you are using an existing Credit Card or ACH Account, and do not have the Id stored in your system, you can look it up the [default card](https://documentation.paysimple.com/reference/customercustomeriddefaultcreditcard) or [default ach account](https://documentation.paysimple.com/reference/customercustomeriddefaultach) for the customer.

### 2b. If the account object does not exist for your customer, add the [ACH Bank Account](https://documentation.paysimple.com/reference/new-ach) or [Credit Card Account](https://documentation.paysimple.com/reference/new-credit-card).

### 3. [Collect a payment](https://documentation.paysimple.com/reference/new-payment) using the account id from step 2.