If I now look at it from Wasps perspective, then they'll have terminated a contract 18 months ago, I can see that a text message isn't the worst way of communicating with someone that you think you've parted with a year earlier.
We have no idea who Pete contacted at Wasps, or who replied to him.
This could very easily have been handled by relatively new members of staff who are completely unaware of Pete's history with the club, and the text may not have been as abrupt as the Twitter exchange makes it sound.
In all, it could certainly have been handled better, but it's sounding less bad than it did first thing this morning.
While Wasps communication could have been better, Pete should certainly have been attempting to clarify his contract status before now given that he knew his contract was terminated 18 months ago