Charged for a "free" service - DirecTV

We recently had a problem, and called Directv. One of your representatives told us because we'd been such good customers (15+ years) we qualified for a free 3-month premium subscription. We received our bill yesterday, and the "free" subscription was charged $6.99 for a partial month, because it was started in the middle of the month. YOUR rep offered it, we didn't ask. YOUR rep started it in the middle of the month, so WE shouldn't pay. We called and told them to cancel the 'free' premium channel altogether if this was an example of the service. Honestly, we're struggling to decide if we're going to continue with Directv or switch to another provider since our bill has gone up considerably but no new channels have been added to justify this. This latest attempt at showing us what a great company you are has decidedly failed, and I would like to know if it's a policy to offer something free and then charge the customer when they accept.

This question, "Charged for a "free" service," is about DirecTV channels, programming, equipment, and sports.