How much does the Mazda dealer charge for a transmission oil and filter change?

I have a 2007 Mazda 6. Has anyone went to the dealer before for a transmission oil and filter change with their Mazda before? I really need to change mine already because the fluid is brown already! So if you have any idea of how much day will charge for the whole thing. Thanks you help would be appreciated!How much does the Mazda dealer charge for a transmission oil and filter change?
I had my transmission replaced, cost me $3,000.00 and oil and filter is about $15.00. Oh but I don't have a Mazda.

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