I don't know why the bank can grant you to use so much until you have debt of HKD300,000. It is a huge sum as based on your job.
But do be careful in your work place to secure the work and at the same time, you need to work a few part time job to clear the debt. Please do not think of gambling in casino, this will worsen your condition.
Suggest you look into 2 ways to solve.
1. Ask help from your brothers or sisters.
2. Ask help from friends.
Not a good suggestion but you can have some hope.
1. Buy lottery in a small amount of money, may strike a fortune but you must not spend much money in this part. This is counting on your 2007 luck.