Wifey has a Samsung Galaxy J5, sourced from Vodafone originally but connected to Skinny.

She does not have, and does not want, any mobile data.

She has now received a few MMS messages, one is a test one from me, that she would like to view.  They all say they come from 9999.

Instead of showing a picture it shows a txt message saying "You have an MMS message ....." and includes a link to telecom.co.nz/mmsgallery.  I assume that is because she has no mobile data.

Tapping on that link when connected by WiFi duly takes it to Sparks MMS retrieval site.  This then prompts to enter the mobile number.  This is where we come unstuck, entering her number on the registration page it returns an error saying it is not a Spark mobile number.

Anything I can do to retrieve these MMS messages?