QR Code Generator Pro does not integrate any ads, either into the QR Codes created through our system or into the user interface of our software. This is completely independent of whether your account is still on the trial or subscribed to a plan.
If you see any ads when scanning QR Codes, these come from the scanner apps that you have downloaded on your device.
Free apps are often financed through in-app advertising. If you want to stop seeing ads, you would need to download a different (ad-free) scanner app.