How do I cancel this as they took $19 from my account as well?

[papermoon.lady]

SmartyCash Plus I assume?

Scroll down to 8.1:

https://www.smartyplus.net/terms

You probably accepted their eBay $15 voucher that started your Plus trial (which became a normal subscription after the trial period because you didn't cancel it).

[brindabella0419]

Going forward, how do we cancel further debits?

[sandypebbles]

As has been explained numerous times (including  in this thread and several others )

Log into the account you created. Cancel your subscription.

It will come out every month until you do it.

The link to do so has even been posted in *this* very thread by another member 

Nobody else can do it for you

[sandypebbles]

The $19 you agreed to when you signed up to Smartycashback

$19 will come out of your account every month (as you agreed to) until you cancel the subscription 

It is in the terms and conditions that you ticked you read and understood/agreed to when you signed up

[countessalmirena]

The thread that I posted explains, including how to cancel.

https://community.ebay.com.au/t5/Buying/Smartycashback-why-you-should-have-read-the-T-amp-Cs-and-how...