if you do leave, they might probably hold your salary and then demand that you pay the rest of the bond. ultimately, you will have to file a claim at nlrc.
if you resign, they may file a small claims case against you, then you can make that argument. unfortunately, the supreme court has ruled that it is unjust enrichment for an employee to resign within the agreed period, but the court has the power to review the agreement whether it is fair in the first place.
it is up to the company to utilize you and your training. failure to do so does not waive any of their rights. your defense is to show that you did not unjustly enrich yourself with the training. good luck.