The Premier League champions were found guilty of “serious breaches” of Financial Fair Play, which also resulted in a €30m fine.
They will appeal the ruling at the Court of Arbitration for Sport – insisting their name will be cleared.
Guardiola has also vowed to stand by the club and fulfil his contract, which has another year to run after this season.
But asked if he’d received any messages of support from within the game, he answered bluntly: “No.”
Guardiola has already hit back at his former club Barcelona after their president Josep Bartomeu appeared to back their punishment. And he was bullish about City’s achievements, regardless of the ruling.
He added: “We cannot change what people think. I know how hard we work.
“I am so proud about how hard we’ve worked all these years.
“No one helped us outside, we did it day by day, game by game.
“This is not finished, it’s not over, we appeal as a club and we see what happens.”
This week City chief executive Ferran Soriano insisted the club’s name would be cleared after claims they’d overstated sponsorship values to circumvent FFP regulations.
He said: “Well the most important thing I have to say today is that the allegations are not true. They are simply not true.
“The owner has not put money in this club that has not been properly declared. We are a sustainable football club, we are profitable, we don’t have debt, our accounts have been scrutinised many times, by auditors, by regulators, by investors and this is perfectly clear.”