So, correct me if I am wrong here...
They sent you a defective rack, you had to convince them it did not fit, they sent you a experimental part to see if you could get that to work (still wrong), insulted you and argued with you, you sent it back (on your dime), you had to get your money back thru your card company.....
Insult you more....
Now, you find the original brace that was too short anyway, they should reimburse you for everything, including rack, brackets and all shipping charges.
I state this because they shipped a defective/wrong item and none of it was your fault.
PERIOD!