Demand letter

I resigned from a company last January 07, 2012. Unfortunately I am not clear with them yet. So my last pay is still with them. In September of 2011 I received a demand letter for an over payment of 15k. There was a payout problem on March of 2010 that is why there was a cash advance of 10k. But when the reconciliation papers arrived. I found out that the numbers are not tally that is why I did not signed the authorization to deduct. Now I don't know where did the additional 5k plus came from. But based on the stories I heard it was for the night differential payment. My dilemma now is that, if i will allow the 10k to be deducted from my last pay but the leaves and overtime pays that was not credited during my employment would still not be credited. and what if the 5k was for the night differential that they were claiming. They have been paying us 15% night differential since my employment in 2006 but they decided that they should have paid us 10% instead? what must I do?

Please go to DOLE to file a small claims, a SENA form then every details ay paguusapan na between you and the company with DOLE mediator.