I’m sorry to hear all of this. However, I hope you recall that I was quite firm in my first response when I advised that you needed a new mechanic. Others in this thread also warned you that this place did not seem to know what they were doing.
I know that you wanted to allow them to redeem themselves (and for you to get back some value for what you had already paid them), but the signs were pretty clear that this place was “chasing a problem” (as UncleTurbo stated), and were mindlessly throwing parts at the situation until they randomly found the solution. Unfortunately, that approach is a very expensive one for the customer. Luckily, I am sure that you have learned a lesson from this experience, and will be a much wiser consumer of automotive services in the future.
With all of that in mind, I have some additional advice that I hope that you will heed, namely, do not waste your time with the BBB. I have been familiar with their shortcomings for several decades, and then several months ago, Smart Money magazine published their investigative report on the BBB, confirming my belief that few consumers are actually helped by this privately held, profit-making “Old Boys Club” for businesses.
The BBB has no punitive or regulatory power, simply because it is NOT a governmental agency. For some reason that I have never been able to fathom, most people seem to think that the BBB is a governmental agency, and it is absolutely not. In fact, the national organization sells local franchises to people who are interested in making money from this type of business club. If it was truly a non-profit organization that functioned solely for the good of the consumer, there would not be any such thing as sale of local franchises.
Some local BBBs actually charge a fee to file your complaint, and if you paid them a filing fee, this would truly be a case of “throwing good money after bad”. Most of their income is derived from membership fees, which is their motivation for protecting their members, rather than resorting to any significant efforts to force rogue businesses to satisfy complaining consumers. In fact, their business model represents a classic conflict of interests.
If you want a better chance of a settlement, contact the Office of Consumer Affairs, which could be either a state agency or a county agency, depending upon where you live.
Good luck!