I bought two Samsung Core LTE phones for my kids for Christmas. They are on text & talk only plans (ie. no data) but it includes MMS which requires data. The default entry in the APN settings is set to allow access to the Internet and MMS. Since data needs to be on for MMS, I would like to remove the default APN entry and replace it with one that only allows MMS access when data is on to avoid data charges. I have tried adding a new APN which allows only MMS but the phone always seems to switch back to the default Koodo entry. I have also tried adding an APN for internet that directs to a nonexistent server. Again the phone will allow me to select it, but it will ignore the selection when I exit the settings and revert back to the default Koodo entry that provides internet access. I realize this is a revenue generator for Koodo but I don't want to have additional data charges for services I do not want those phones accessing. Thanks!