I never was told for extension, that dez guy is making up stuff by himself.
He notified you a day in advance before the deadline and seeing as you had availability on Sunday you had time to notice/respond to it. The time between you two was never confirmed so just showing up at the time that
was not agreed upon by both parties isn't enough to claim activity. There was also no message of "im on this server as x" which also would've helped your case. As such, the extension will go through.