Milestone Credit Cards complaint: Adverse action on a credit card dispute

I canceled an order at Regency Furniture store for sectional furniture that I did not receive after waiting three months (outside the 4 to 6 weeks of the delivery). Regency Furniture reversed the majority of the charges that were placed on my Bank of America check card, but after many attempts to reverse the charges on the Milestone credit card, they failed to do so. I disputed the charges in November, with a copy of the invoice, that clearly states the item was canceled, and a copy of my Bank of America statement showing that the charges were reversed.

Regency Furniture gave me a 500 dollar credit to their store because they could not reverse the charges. I did not the credit because the item was canceled and I refused to bite the bullet after that failure to reverse the charges after so many attempts. I reached out to Milestone with all the pertinent information and they refused to reverse the charges.