If you supplied the parts, that is a ridiculous amount of money.
I'd be asking why it took so long.
I had an interesting discussion with a garage some time ago when they broke the oil cooler on my Alfa 155. The garage phoned and said they'd broken it, and the replacement would cost £X would that be okay. I said that's be fine as of course they would be footing the bill.
They said that it wasn't their fault that it broke, it would have happened anyway.
After a lengthy chat they agrees to replace it for free, but only when I said that a professional, competent garage shouldn't break parts and expect the customer to clear up their mess.
I'd suggest calling a couple of local garages and asking for a price for the work you have had done. Then going to the garage that did the work and refusing to pay more than say the middle quote of three prices.
However, I future always ask for a written quote including a worst case price. A set price the work will never go above. Garages can get twitchy on that, but it's saved me huge amounts of cash over time.