With or without contract, if you have been allowed to work 1 day after your 6th month period, you are already deemed as a regular employee. If you want to leave the company, you must submit a resignation letter 30 days before leaving.
The company have the right to hold your last salary, to be released as a last pay. last pay can be released after completing a clearance form.
The company have the right to declare payment of your training bond and you have the right to declare that you are not liable for it since you did not sign any bond agreement. You and the company will be fighting for your final pay over this. This may take months or years to finish.
Good Luck.