You are entitled to the receipt of written particulars of your employment agreement. Ask your employer for these particulars to avoid confusion as to rights and duties.
As for leave - where your agreement is silent, the Basic Conditions of Employment Act provides the default position. Usually, one is allowed one day leave for every 17 days of work, which amounts to around 15 days per year. If the duration of your annual December shutdown was shorter than 15 working days (3 weeks), you probably had some leave outstanding.