NOT RECEIVING OTP SMS ABROAD

[Howler11]

Hi 

Does anyone have any advice , when I sign up for website registration abroad eg to buy coach tickets when the OTP is sent I never receive it , have tried all variations +44 laving the 0 off , adding the zero , nothing comes through. 

I have tried speaking to chat but they didn't understand  .

i am on monthly unlimited contract 

[Howler11]

im in the uk at moment , received OTP from bank , now just tried signing for coach in italy and no luck, so not sure if the roaming would apply.