it is proof that people in the Trump campaign were under surveillance by our previous Administration.
Untrue. It is proof that someone was under surveillance. Because people in the Trump campaign were interacting with people from Russia (which no one is denying, at least on a superficial level) it is possible (if not quite likely) that the Russians were under surveillance and that is why the Trump campaign got caught in the net.
The problem is that Trump and Spicer shot their mouths off with no proof to back it up.