Work completed by a shop either caused or was not correctly diagnosed?

Outcome after $2100 paid repair, owner states now wants $5,500+ to replace transmission.
I am a single disabled woman and tomorrow I will be chronologically 68. On May 30 I decided to take my vehicle to be fixed. I chose to go to a shop I had never previously used. The vehicle had started having issues with overheating. Initially I tried Auto Zone for the purpose of discovering what information could be gathered from diagnosing the check engine light. The tech determined simply overheat.

The service advisor called and informed me details noted on photo. Since they had found numerous other issues adding much more money, I asked to speak to the owner before authoring the work. I asked him if I could be certain that if they proceeded the radiator, cooling system and air conditioner would be died and he replied "absolutely".

After driving a short distance I returned to the shop stating it was running ruff and the air conditioning was not blowing cold.

The soonest they could get me back in was 06/05. They did not even look at it until 06/06, when they came up with an additional $550 of work.

They next time I drove it, it was making the same shaking. I called and asked if it would be fine to drive less than a few blocks to bring it back. By the time I got there it was not moving out of first gear. The new front desk person (the one I was working with I was told was fired) called with the news that the transmission would need to be replaced.(06/17). With every use toon his replies became more rude and condescending. I left it that I would need to speak to the owner.

I am an honest, perhaps too trusting person. After reading your posts I fell that they were negligent on many counts and feel I should at least be refunded for $2000 + I paid. I am left with a vehicle that I cannot afford to fix.

At post time I have yet to speak to the owner. My gut told me to do some investigation. The newly hired person stated that there was no negligence because they could not see the future. Nonetheless there are numerous videos the forewarn mechanics that, especially with this year and model, that with any kind of overheat to check the transmission / radiator connection and always replace the radiator with a cap issue.

The vehicle it is their back lot. The second receipt for the word done one the air condition is unfortunately in the vehicle. It was approximately $540.

I have worked hard since I was 12 and was raised that my word is the most valuable thing. If this is simply bad luck as they are claiming I can take it under the chin. My gut tells me otherwise.

If I was your wife or daughter, what is the right honest move? Thanks a billion! I will definitely contribute before this is all done.