Sell at home and buy again.

I did exactly this last year from Australia,and Qantas, refused to check me in without evidence of leaving Thailand within 30 days.

So I quickly got online and bought a cheap airfare to Vietnam within the 30 days, then showed them the receipt, they then checked me into my flight.

I guess now it's 60 days but will need evidence of leaving.

A bus ticket or boat or train or plane anywhere out of the country will do.