Block a number from SMS - think car warranties and google listing calls

As luck would have it, the number we were assigned for SMS seems to get some spam messages and there is no way to block numbers.  Since SMS is a premium feature that we pay extra for it would be nice to see some extra features included like caller ID blocking.  Don't get me wrong, I am considering extending my cars warranty, but I'd prefer not to have those messages in OR.

We get 2-3 spam calls per day on our SMS number. I have the number labeled "OwnerRez Guest" so I know to always answer when it rings, but unfortunately 9/10 times it's just a spam call.