Unable to Respond to Text Abroad

[ST3V3]

I’m a relatively new Three customer, with a PAYG SIM. On a recent trip to the USA, Go Roam worked exactly as I expected/hoped it would, with one exception.

I had a text message from my credit card company asking me to confirm some transactions, and I was unable to reply to it.

The text message came from 61175, asking me to reply with a Y or N. It was a legitimate text (confirmed by my credit card company), but I couldn’t reply. Every time I tried, it said Not Delivered/Message Failed to Send.

Is this simply because I was trying to respond to 61175 from another country, or should I have been able to reply? Grateful for any help/insight in case I’m ever in the same situation again.

[ST3V3]

Yes, there was a £15 credit balance on the account. So even if it wasn’t included in my Go Roam bundle, there would have been sufficient credit to cover the cost.
Re legitimacy of the number, I had a separate text from my credit card company advising me to expect a text from 61175 (and then a phone call afterwards as I didn’t respond to the text) - so I’m as sure as I can be. I haven’t tried to respond since getting back to the UK. 

[jr0]

I see...
well if you had credit and potentially replied to "pure"/true SMS (in case some of your contacts not use RCS their android) I can only think of something else on Three side (e.g. misconfigured for 71165 short code ??) or maybe @JadeF is correct, and only Three support team could come up with the true reason for it 
I understand that it doesn't make sense for you to reply now to 61175 🙂