Old and new device charged

I received SMS that I was due for an upgrade.Went to store, upgraded, that was end of July. I called customer service last week since they deducted for new and old device since August. According to the consultant that helped me, said on system it shows that I was eligible for an upgrade, but they charge me for early upgrade. Received an ref no and I was waiting for their call. I'm not sure whether they phoned since I worked night duty,but no calls from them. Ref : ***. Please give my back my money