There’s a few potential reasons why you’re not receiving your OTP. Your bank sends the OTP required to link your card using 3D Secure. Please check which phone number your OTP is being sent to by your bank. Another potential reason could be a slow cell phone network. It’s important to remember that OTPs are only valid for 60 seconds. So, if you have asked for the OTP to be resent more than once please use the last OTP you received.
If none of that works you could always try switching your phone off and on again. That generally does the trick.