Overcharged for McIntosh Service?

I recently took my McIntosh MA6100 to a local repair shop that is an authorized Mac service site as the right channel was dead. I had to leave a $40 deposit to cover the cost of the diagnostic to be applied to the repair bill should I choose to have it fixed. I was told I would receive an estimate by phone before the work was to be done. Several weeks passed and no call. I called them yesterday and was told 2 fuses, 2 output transistors and two driver transistors need replacing for a total of $270 (89.00 parts and 180.00 labor). When I questioned the cost I was told the work had already been done. They assumed since it was a McIntosh I wouldn't balk at the cost so they didn't bother to call with an estimate. When I voiced my concern as to the high repair cost and the lack of an estimate I was told my only recourse was to have them open the Mac back up put the old parts back in and forfeit the $40 deposit. Also I was told that now when I turn it on there would be a hum during power up which dissipates in a few seconds which it didn't do before. In order to fix that it would be even more money.
I got a real bad feeling and just wanted to get my amp back from this guy so I wrote a check for the balance and picked it up. The right channel does work and the hum although I really don't recall it before the repair does stop in a few seconds after powering up. In addition to the obvious concerns regarding the lack of an estimate and the hum I question the validity of $180 for labor. Looking back I am tempted to stop payment on the check and negotiate with this guy offering to pay for the parts and split the labor which totals $180. Am I being unreasonable?
Sorry, but 180 for labor isn't excessive. If the unit works and sounds good, consider it the cost of audio and move on. Certainly, they should have called you with the estimate. However, assuming the work was performed and resulted in a functioning component that you valued at greater than the total repair cost, then call it a day. Just MO. Enjoy.
It would be interesting to know how the shop arrived at $180.00 for labour. Was it two hours at $90.00, four at $45.00? Seems to me that either the hourly rate is quite high (may depend on your location, though) or that it took an inordinate amount of time to complete the work. It may have been some flat rate or some rate prescribed by some manual as used in car repairs. Anyway, not calling you with a quote is not very ethical/honest, but that appears to be par for the course these days. Like the other man said, the only pratical thing you can do is move on. I am curious as to the hum, one would think that they would have told you exactly what is causing it and what can be done to fix it, especially if they are so proud of their association with Mac. If it provides any form of relief, you can thank your lucky star you did not have to ship the unit across country or, worse yet, from Canada to the States, for repairs.
Yes, they should have given you a quote (as mentioned @ the start), but the repair cost seems pretty standard. Around my area 1.5 to 2.0 hours of shop time is the norm (even for small repairs). If it sounds good to you now then forget about the repair cost and enjoy the amp. If not, then try to work "with" the shop first. This is what I would do anyway. The line that most Mac owners would not complain is, of course, a crock. I have owned vintage Mac tube gear and always shopped around for basic service. The shop with the lowest cost "quality" work got my return business.
I have to agree with Jcbtubes above, that I don't think you
were overcharged for service on your McIntosh unit. Your McIntosh unit is an older one; and not only are number of the parts needed for service only available through McIntosh, but few electronics repair services can properly
service your unit.
I do have to fault the dealer for not calling you prior to repairs being made - but for little else. I'm not sure if
you've had any consumer electronics serviced recently - but
the labor rates have gone up a lot in the past few years.
My experience is that it is better to pack stuff up
and send it to the McIntosh factory for repair. I have
had nothing but excellent work from them and not costly
bills; in some cases, they didn't charge or undercharged.