They cancel your extra baggage allowance that your purchased directly from Jetstar and give credit back to Qantas without telling you

I brought ticket via Qantas point from Adelaide to Melbourne on 18th of May and add extra baggage directly with Jetstar and paid with my credit card. later on I decided change my flight to different time, after i changed my flight i have asked Jetstar online customer service if my extra baggage will transfer to my new ticket, they told me "yes", at meantime they ask me my name and ticket No. so I thought it was confirmed. Also I was smart enough to ask Jetstar send me that online conversation to my email.
when i went to check in , guess what !!!!!!!! they charged me $225.00 and told me that i didn't purchase the extra baggage.
I have no choice but pay for it as my flight departure within 45 mins.

Next day call to customer service , guess what they told me? "Because you changed your flight , your extra baggage was cancelled by Qantas frequent flyer team and money was credited back to Qantas and you should ask Qantas for money back"

1. what is the point I paid with my credit card ? this additional baggage contract is between me and Jetstar , not between Jetstar and Qantas.
2. When you extra baggage was cancelled, don't event bother to inform the person who paid for it ? what hell is this logic come from ?
3. As soon as changed my flight , I asked Jetstar staff online if my baggage will transfer , why Jetstar ask my itinerary detail and tell me " yes, it i will auto transfer" and it was not.

BTW , Qantas even worst , they told me that Qantas and Jetstar are totally different company. I mean really? Jetstar allow you cancel my extra baggage and credit back to you for god sick. how both of you lied about this, I am sure Qantas and Jetstar is big lying "family"

Never flight with them again , I feel funny all those big companies always talking about customer service and they never really cared.

Australia-Melbourne - Tullamarine