As far as I know, MMS text messages are controlled by the carrier and not necessarily the phone. Unless you installed a 3rd party app that controls MMS, there are no settings within Android that can disable MMS. That said, it would be best to contact your service carrier for technical assistance with the account.
I'm using a Samsung I7500 Galaxy and for some reason, I can send pictures but when my contact sends some I don't evne receive them. Is this with all the phones or is it something with my phone? Also if this is an option that has to be enables, please tell me how I can. I've only been using this phone for one month.