That's a lovely story.
I can't believe they wouldn't accept your phone number though. I can understand that their system may not be equipped to accept international phone numbers, but in that case if I were the cashier, I would have said, "Oh, I'm sorry. Our system won't take international phone numbers, but no worries - I'll just put the store's phone number (or a fictitious one, or even my own if nothing else) in."
Well at the time (remember there is only 4 million of us and the sheep tend not to have phones), we only had 6 digit numbers, and with the area code being the 7th there was not digits to fill in. If I had thought things through I would have told him to add a couple of noughts, but things were a bit fraught and I thought he was teasing and he wasn't. He added that I should repeat the number again but in english this time, which really got me irate and I think the nice gentleman behind us was a little embarrassed by the whole thing. He has a really nice family though, and we regret we will not be able to meet up with them in Hawaii next month.