Big C yes I do that all the time there so no Issues.
But 7/11 I have asked many times and every time it was declined and it was Wallet or Cash only they said
Edit: With QR Code Scan, I mean opening your Bank App (SCB, BBL, KSK Etc etc) and on terminal they show a QR code and you scan that with your Banking APP (not with 7/11 app or TrueMoney app)