Unable to recieve code to disable imessage

I'm trying to disable imessage without access to my iPhone. Whenver I use the web bases self-service system to disable it, but (I'm assuming) the confirmation code sent to the phone number is intercepted by imessage, the very thing I'm trying to disable. I have already confirmed it is not a carrier/Sim card issue as I am able to get mms messages from other android users just fine.