Having to fight to get my money

I bought a vehicle in June 2019 and had a trade-in. There was an amount payable to me after the settlement of the outstanding amount with the finance company. The dealership requested a new settlement amount from the finance company in July, after July's payment was deduced from my account by the finance company. This means that the settlement amount was less than the original quote in June and that the amount owed to me was more, but they only paid me the amount based on the original settlement amount of June. This was brought under the attention of the salesman on 19 July, which he acknowledged, but after numerous calls and emails, I have still not received my money owed to me by Rally Motors (end August). The initial service I received from Rally Motors was great, but the whole experience afterwards soured my dealings with the dealership.