I Want to Block Incoming Texts

T-Mobile has no control over texts that use iMessage.  If those texts are coming in as SMS/MMS, incoming texts are usually free.  

I mentioned iCloud only because I can't tell which SMS messages are coming in via my T-Mobile number vs. those that are coming in via the other number.  I want to turn off the messaging feature on my T-Mobile number altogether so I am not incurring fees.

Scott60 wrote:

I mentioned iCloud only because I can't tell which SMS messages are coming in via my T-Mobile number vs. those that are coming in via the other number.  I want to turn off the messaging feature on my T-Mobile number altogether so I am not incurring fees.

You can reach out to Customer Care via 611 from your T-Mobile number or send a DM to T-Mobile on Facebook or Twitter to see if that is possible.  You should be able to select a SIM to use as tour default SIM in I messages though.  Messages over iMessage use data unless they are specifically SMS/MMS to or from non-iMessage users.

There are a few different message blocking features that can be added to your prepaid account to block different levels of messages. You can limit it to chargeable messages or block all messages. None of these messages should prevent you from getting the free messages that are sent to you like account notifications. Most of the time you can add the blocking features by logging into your T-Mobile account online or on the app. You can also do what Syaoran suggested and contact one of our care teams to have them clarify which feature you need and get it added for you. 

Scott60 wrote:

My "free" text message allotment to my T-Mobile pay as you go number have been used up by unwanted incoming spam messages.  I want to turn off text messages on my iPhone so I do not incur additional fees.  My iPhone is connected to an iCloud account, that also has another number on a different account - so I can't tell which messages are being sent to my T-Mobile number vs. the other number.  This guide is about blocking messages, not avoiding overage fees.  How can I turn off incoming texts and avoid overage fees that are being caused by unwanted spam? Maxim Time Clock

-Mobile may have specific procedures or tools to help block spam messages or manage your account settings to prevent overage charges.
Consider using third-party apps from the App Store that specialize in blocking spam messages.
If your iCloud account is causing confusion between numbers, you may need to adjust your iCloud settings or iCloud-linked devices to ensure messages are correctly identified.