Customer Despair

I had purchased a Ceres juice. The bottle was sealed but the contents were leaking. I first contacted Ceres on 21 June. After four days and no reply , I phoned the call centre and I was promised a reply within the day. By the next day, no reply was received. I then contacted Ceres again. After being thrown about, I decided to contact Pioneer foods. I was referred to Carol Brown, who is the customer complaints coordinator. Initially, I had a very pleasant experience. I was contacted via email and telephone, pioneer foods apologised for the faulty item and lack of service by Ceres, and then a date was set for the collection of the faulty product. At the same time I was promised a voucher to be delivered at the same time of the products collection. Anyway, the product was collected and sent to the laboratory, but no voucher was received. I then contacted Pioneer foods once again, one week after the product was collected. I was promised (again) a voucher will be delivered and feedback from the laboratory will be forwarded. To this day, I still await this. It's been almost a month since this issue began. How much longer should I listen to broken promises?