If we go over the scan limit, does the QR Code stop working or does it stop collecting data?

The scan count represents the total scan counts of QR code when anyone scans it.
Every plan has a scan count limit given and once the limit reached before the month ends, your display page of QR code will be paused.
You can choose your plan to extend the limits of QR code scans. Our Ultima package comes with unlimited scanning options, but in most cases, 150000 per month scans in the PRO package are good enough.