Vodafone Failed to Deliver on Refund Promise

I was told I would get a refund for my expensive Vodafone bill, but they haven't given it to me yet. Even though the customer is called and told that they are always right, that's not always the case. One representative said they got a refund that was approved, but another representative is saying they didn't get it and blaming it on wrong information. Why would you promise a refund if that's what's happening? Also, another representative proposed an upgrade plan that included a red tariff but ended up providing something different. I've been with Vodafone for 8 years now, and today is a special day because it's my anniversary. However, I'm thinking about switching my number to a different provider.