Hi MelissaVIP,
Here's a handy article to help turn off online invoice payments: Turning online payments on or off.
Just a heads-up, it's expected that the system still shows the service as active because the online payments feature itself hasn't been fully cancelled, only disabled for new invoices.
Please note that if the service is fully cancelled, you may be prompted by the system at a later stage to go through the verification and setup process again if you decide to enable it. So keeping it active but disabled is often the simpler option.
Regards,
Sai