Mavis Discount Tire

Mavis Tires & Brakes at Discount Prices on Touchton Road in Jacksonville, Florida had a "Mixup" yesterday (12-28-2021) that just turned my $2, 500 quote into $185 (to solve the same problem). Of course, even given my lack of mechanical knowledge, I knew right away what was going on when they initially hit me with a $2, 500 quote.
Recently, I had a "Check Engine" light go on (not long after a thorough tune-up by the well respected and highly recommended auto shop "Willards" in Jax Beach...love those guys and have been using them for over a decade, and I only wish this problem had popped up weeks ago).
A Mechanic Friend of mine (with a mobile repair business) https://www.facebook.com/PrestigiousMR/posts/1069969443360870 scanned my Honda Civic and discovered the problem was related to a P0128 code, which involved the thermostat and the temperature censor. He suggested I take it to a shop and have them replace both and he estimated a charge of $150.
So I took it to Mavis, an auto shop who has been good to me in the past. I immediately notice there are new people working who I've never seen before. I think nothing of it, drop my car off and explain to them the details passed on to me. A few hours later, the gentleman who was working with me called me around lunchtime. He tells me the original quote was $2, 500, but he was able to get it down to $2, 100 for me LOL! How generous.
That conversation didn't last long. I immediately consulted with my friend who advised me that this sounded like Robbery and to pickup my car. I agreed and I was already onboard with this advice.
So I call the guy back and tell him I'll be picking up my car and that I would like a full itemized breakdown of their assessment. He started to sound uneasy. He then told me that was fine but there was a $129 diagnostic fee. If this were a legitimate circumstance I would have no problem paying any reasonable amount. But this felt like a scam. He then said he could work down the diagnostic fee. (I paid ZERO).
I return to the shop and I see a man sitting in front of the TV. I asked him if he worked there, and he said no. So I told him to be cautious with these guys as I felt like they were conning me. The man told me he was starting to sense similar feelings from his own situation.
A few of the employees returned and I confronted them as to why they were charging me nearly 1, 400% more than was required to fix my issue. With other customers in the room listening, the man argued with me, seemingly offended that I would doubt their diagnostic report, and then he called someone, allegedly at an auto shop, to confirm over the phone the cost of the repairs. I giggled and said this phone call was meaningless to me, and that I was only concerned with his printed assessment. I told him he tried to bluff the wrong guy and that I would be getting a 2nd opinion and would post the results in publicly visible review forums. I then demanded my car be prepped for my departure and that I didn't have all day as they had wasted enough my time!
I went home. Not even 10 minutes later I get a call from the guy apologizing that there was a "mixup" with another quote (what a coincidence!) and that my actual quote was only $185. I literally laughed and hung up. He then called me back again 5 minutes later to attempt to explain the situation again. I suggested he email me the fine details of the mixup (that would be auditable) and he declined stating that he was telling me over the phone. I again laughed and said I was no longer interested in this conversation and sent him to the dial tone.
Do any of you actually believe these guys had a "mixup" that massive? And, in addition, do you believe that if I had paid the $2, 100 that they wouldn't have taken it all way to the bank?
In my opinion, based on conversations with others (and literally this guy's own admission), I no longer trust Mason Tires and Brakes on Touchton Road to be a legitimate and respectable auto shop. Take your vehicle there at your own risk.