similar issue was I was getting non stop text messages from a shortcode I had never seen TMobile send a text from before and it had to do with my mobile hotspot being at 80% use for the month when in actuality I had used zero.
I received over 30 messages and a 20 of them while on the phone with T-Mobile and wound up just blocking the number because TMobile can use any shortcode that they need to get ahold of you.
Hmm, there's definitely something going wonky if you're getting rapid fire messages from us. Are the still getting those messages? You can get our Team of Experts folks to file a Service Desk Ticket if you Contact Us.