How to receive back my down payment on BOGO phones?

Hi.  I am frustrated with the BOGO offer because I ended paying for more than I needed.  I got four phones when I only needed two phones for my family plan of 4.  The salesmen at a corporate retail store had informed me that I was placing a down payment for both pairs of the "free" phones and the paid phones while receiving the credit in 2-3 billing cycle.  He had also said that the down payment for the two "free" phones would be credited back to the bill in full after 2-3 billing cycle (~total of $400).  So that day I paid downpayment of $940 upfront.  

I have spoken to a different ATT store manager after I checked my bills within 2-3 months.  The monthly installments have been crediting fine but I am still waiting for that down payment on the two "free" phones to be credited.  The store manager told me that any down payment on BOGO phones should have been credited back already and to call the customer service about it.  I called customer service and a case number was opened up for me.  They have understood that i paid two times the down payment required.  24 hours later, I receive an email that the case is closed.  I called the support number for the billing department of ATT and they go around in circles telling me all the information I already know about the BOGO phones being credited monthly.  But they denied crediting the down payments on the free phones! They told me that I would continue getting credit after the 30 months is done.  I don't see that in the agreement for the BOGO offer.   That would mean that the phones are not really free! How else can I get my money back?

The phones I got were:

Samsung Gs7 ($650)

Iphone 7 Plus  ($869)

BOGO offer includes credit up to $650.  I understand if the iPhone 7 plus down payment will not be credited due to the price amount being over $650.  But the Samsung GS7 should have gotten me my $201 credited to my ATT account.