I said that Allah SWT,His Prophets and the believers are disbelievers (kafirs) in taghut,which means they disbelieve in it as the Quran mentions,does this make me an apostate?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Just saying this expression does not make you an apostate even though attributing the disbelief in Taghut to Allah is something that is not mentioned in Islamic texts – as far as we know.

Therefore, it should not be said about Allah Almighty.

In any case, we advise you to avoid whispers and ignore them, and seek to treat them.

Allah Knows best.