Nees help in integrating Pine Labs POS handheld devices

We have just implemented POS and it is working fine but we have a need to integrate Pine Labs handheld device for processing payment.

Here we have to show a QR Code (for UPI) to the user on the device and as soon as the user makes payment the POS has to print the invoice/bill without preview.

If anyone has any ideas or suggestion please do share them.