I always hate reading stuff like this where genuine people get ripped off.
One thing people have got to understand is price you pay for services. If you go to a shop that you like the quality of their work, get a quote for the work you want done.
Now if you try and get this price down and succeed, you can hardly expect the quality to be of the originally quoted standard.
When someone quotes a job they look at materials, time and how many workers it will take. If they cut the cost for you, they also have to cut their costs.
In my industry if you want your car rewired in 2 days you pay a price, but if you want it cheaper, the only way quality can be kept the same standard is if the job is done over a few weeks in spare time when no other better paying jobs are around.

I truely belive its a shame that most shops dont show this fact to customers ( Price + Time = Quality) This is why Dattodevil pointed out that you get a greater percentage of Cowboys instead of Tradesman. Its also a shame that some customers do everything to try and get the best job done but things out of their control happen to the situation.

Regarding no work being done for months comes down to the same thing ( Price)
Higher paying work gets priority. Might sound harsh but when your paying employees and workshop bills you cant treat every customer like a little brother.
If your getting something done, go into the shop everyweek or atleast phone to check progress. Even if you know that for your quoted price chances are no work will have been done yet. Just show the workshop your whatching and keen to get it moving.
If at any time your not happy you can take your car somewhere else but you still have to pay for work already done. ( Atleast you stoped the bad work when you where unhappy)

Another reason that I say to go to the shop or phone each week is because some customers dont show up for months. If a customer doesnt show up I wont start work as I am not going to do a job and wait 6 months to get payed (Its not the workshops resposibility to call you. Its your car)
I once had a customer drop off a RX3 to fit a computer and full rewire. He was a good customer who always payed good money, he never questioned a price, just payed and thats it. 2 weeks later he came in and payed 3 quarters of the bill before work even started. We did the job over the next month and then the car stayed there getting moved in and out of the workshop for 11 months untill one day I saw him at a car show and asked him about the mazda. He said hang on I sold that RX3 around half a year ago. The next week he came payed for it and took it. (He didnt even know he still owned the car)

By law in NSW( most likely other states also) if a car is in a workshop for 1 day more than 3 months without the owner showing interest the workshop legally owns the car and can do whatever they like with it.
( Please Make Note Of This)
Now days if I (same as many other workshops) have a car like this for over 3 months, My accountant will send an invoice to the customer for work carried out and storage. If you wish to continue work on the car, fix the bill to date and the storage fee will be removed. If you still show no interest in the car, upon 5 months the car will be sold to recover only my costs.
Thats me, many other workshops will simply sell the car and continue on making a dollar.

Its a sad way to do buisness but Customers and Cowboys lead it to this.

Cheers Steve