I have been working in a shop for a whole year as a part time employee and I have around 180 annual leave entitled. I have moved to a new shop with same owner but my annual leave in my pay slip has been rested to zero. When I asked the employer to pay or fix my leave accrual he just simply refused to do so. I don't have a written signed contract and the only proof is the pay slip. What is the best action under employment law?