The payment type does not matter as long as you have a customer email or phone number on record. The reward is tracked by the customers email address or phone number. If the customer changes their card, as long as they assign the same email address on the first transaction with the new card, the rewards will accrue towards the same email address. This is similar to receiving a receipt on the same email when using different cards. Below are two options.
Option 1:
a) Find customers using the "Customers" app on Clover
b) Start the order from the Clover customers app, so the transaction is linked to the phone # listed in the customer's record, UMarket will automatically detect if the phone is an existing customer/phone number and accrue towards their rewards.
Option 2:
a) On Register app when you are on the Payments screen, you will see a UMarket button.
b) Tapping on the UMarket button will bring up the below pop up box with the following options - lookup an existing customer, add new customer or simply validate the UMarket coupon by the scanning the QR code. 
c. Tapping on "Lookup an Existing Customer" allows you to check if a customer is already signed up to receive your promotions. You can search by name, email or phone number.
d) Find an existing customer or create a new customer and "continue" with the transaction. The customer must have an associated email and/or phone number.
e) Cash customers will receive credit towards your rewards, the same as credit/debit card customers. The rewards are send by email or test messages per your subscription plan.