Rude management

I bought a bed from lewis Richards bay Esikhaleni branch, there was promotion of 300 voucher when you purchase the bed. First of all delivery took 2 weeks instead of 2-3 days and there was no update as why it took long I had to call and go yo the store for followup, when they finally delivered my bed there was no shopping voucher, went to the store to enquire their branch manager Avinash was very rude he told me I should have read the terms and conditions, since I bought cash I don't qualify for a voucher. I have the picture of their promotion it doesn't have any T's and C's