15% 是withholding tax rate and the company must give income tax department 1 month notice before you resign.你有跟公司说要回国？是不是刚拿到pr? withholding tax 是对国外收到singapore income 的人或公司。reaccording section 13 of the income tax act of singapore, you must submit 20% tax because you are foreigner（税率跟公司一样的，但是有一个对外国人的withholding tax rule requires 15%). if your employment exercisd in singapore for not more than 60 days(也就是说59天才不用交tax) in a calendar year, your employment income is exepted tax. if you work in singapore more than 183 days, you can select resident rate or non resisedent rate ( resident rate 比较低， 低于2w不用交税，还有可以claim personal relief;non resident 就不可以了,tax rate 跟公司一样（20％）或给你15％）. if you are less than 183 days, you are considerd as non-resident in singapore and will be liable to singapore tax. however, you can claim section 40 B relief.第一种情况： the relief is based on the higher of (1) flat 15% or (2) the resident tax rate payable on your employemnt income after deduction of all personal reliefs to which you would be entitled if you were a singpore redident.( as singapore resident, you must work in singapore at lease 183 days)

第二种情况： a non-resident professional work in singapore are subject to final withholding tax of 15% on their gross income .

鉴于你的情况， 最大的可能是工作了124 天（31*4），少于183天，是要交tax,因为你在这一年里工作没有到183天，不可以享受resedent rate and personal relief.正常的情况是，在你申请辞职后的那一个月的工资要扣除withholding tax才到你的手上。也就是说你要辞职一个月以后才可以拿到你的钱， 如果公司不通知tax department公司被罚款的。

收到notice (1) agree---->pay

(2) not agree--->pay first---->notice of objection
(3) not pay--->fine s$1000 or jail <6 months