Very easily, swiftly, all they need to say is:

The agent made a mistake, a genuine mistake. But everything was provided to you in the sales kit. The unit number is correct. The floor plan, layout, everything was provided to you. The developer is not at fault.

Don't know how to look at floor plan?
Don't know how to look at building layout?
Don't know how to check the compass?
Don't know how to look at maps?

You signed the S&P, you are responsible. People these days treat signing document like play sand. As if you have no responsibility.

You can trust in God, everything else bring data.
People give you data, you never read never check.
Who you want to blame? Blame yourself lah.