Getting rid of certain configuration messages
Those configuration messages are sent as SMS, so you'll find them in your messaging application – where you simply can delete them:

Usually, long-pressing on a single message opens a popup-menu, which a.o. holds an item to "delete" the message. Hit that. With some message apps, this reveals check-boxes next to each message in the "thread", which you can tick before hitting the final "delete" button – and gone they are.

You might also be able to long-press the entire "thread" (if those messages are grouped into one) and have a "delete thread" item in the popup, which even would speed up the process (no ticking each message separately).