RE Agent sent 6 month lease, signed & receipted by all, now wants us to sign 12 months admitting they screwed up. Threatening eviction if not signed. Help?

We originally wanted to extend the lease for 6 months. Denied but was offered 12 months. Wrote back saying ‘ok whatever’ but then they sent us a 6 month lease agreement.

We signed the agreement, the RE agent signed, all receipted and received.

Agent now saying the only reason why the owner is extending lease is that we said ‘ok’ to 12 months and they messed up & sent us 6 months instead.

Agent now threatening eviction if we don’t sign 12 months.

We are not privy to any internal issues at the RE that could have predicted an error on the issued 6 month lease agreement offer. We received the offer as it stands and under the impression that the owner had changed their minds since offering a 12 month lease - again, we are not privy to any internal discussions that could have changed the owners mind so we accepted the 6 month lease agreement.

From my understanding the signed & receipted 6 month agreement is a legally binding document that should be honoured.

What’s my options? I have contacted QStars, they’ve said that the 6 month agreement is valid since signed and to put in a dispute resolution to the RTA (done). Does the RE have a leg to stand on? We only want 6 months because we are relocating elsewhere in 6 months.

QLD for reference.