Customer 2 (bad)

We had a customer who did not buy anything from anyone in the store so none of us are making commission off the sale, she comes in "i bought 3 phones about 45 days ago, they told me if i bring my old phones in you will buy them back and payout my old agreement with my previous carrier". So i explain, yes this is true, i just want to make sure you were provided all the information before we begin the process (knowing some people do lie, omit information, or assume some things to get the sale). So miss the requirements are it must be the old phone on the account, are the phones you brought in those phones? She replies "yes". Ok next they will need a copy of your final bill with the termination charges clear and easy to read, do you have that ready for upload when you get home? She says "no but i can get that today". ok excellent, and finally lets see those phones so we can buy them back to take care of those charges for you, as long as they are fully functional, no cracks or liquid damage on them we can continue. "What do you mean they cant be cracked they never told me that!". Now shes yelling at me and all i'm doing is trying to help her, yes miss that's one of the requirements. "Yeah well they never told me that so you can make an exception for me". At this point i'm thinking a few things, 1) i'm a middle man and am allowed to turn you down for not buying from us and just send you online but i didn't because i don't believe that's the right thing to do. 2) Your giving me an order? no no no, you can ask but simply ordering me to do something is not going to work. 3) I am not the one to make the "exception" i just get the process started. So i tell her miss, i will be more then happy to buy them back from you but i just want to inform you that when they review it if they see it damaged they will not provide the buyout, I've seen this happen before. The reason they buy the old phones back is to use them to cover your cancellation, through refurbishing them, scrapping them or whatever they do that's how they cover the fee. Then she yells "No this is unacceptable why wont you cover my fee when they never told me they couldn't be cracked! You need to cover it right now or i am going to speak to your supervisor!". Now i'm thinking is she an idiot, didn't i just tell her we as a store do not cover this charge? Didn't i just say i will be more then happy to do this for you anyway i just want to make you aware? Is she just ignoring me blindly focused on the money shes not going to get being all pissed? So whatever i just tell her no problem, im the only supervisor on duty today and as i mentioned before i will be more then happy to buy them back from you and cover our part of the deal. She says "Finally your doing what i came in here for". I'm thinking seriously? I told you from step one i will help you and you are blindly being pissed at me for providing you with information like your original sales person should have and your going to act like this? I have a feeling the original person said something along the lines of "as long as your phones are in good working order" assuming the customer would understand that means no cracks and being the general line for this and she said "oh yes they work" omitting them bring cracked not seeing that good working order means not cracked either which i can understand, however, 2 of the 3 phones didn't even turn on and she said they were working? So whatever i bought them back she got less then $10 for 3 phones to cover her cancellation of over $600 (according to her) and i really hope they did not give her the money because she does not deserve it for her stupidity thinking the customer is always right. Let me know what you think in the comments, was i in the wrong here? Was the customer in the wrong? Or even the original sales rep? I don't know who sold it so its hard to speak on them when i was not present for their interaction but i can make assumptions from her attitude how their interaction went down.