Ok, it's very unfortunate that the latest MT4 1420 update caused you problems and money loss.
It's ok you can still go back to the previous version 1415.
Well, my first question, is your MT4 version on Macbook installed directly? I mean from a broker or MT4 official website?
If yes, that means your Macbook macOS version should be maximum up to macOS Mojave because MT4 does not support any newer macOS from Mojave.
So, if that is true in this case it means that you need MT4 1415 .pkg file for macOS to replace back to 1415 version which I don't think somebody has this file because most people use Windows computers.
But if you have a newer macOS version and installed MT4 windows version on your Macbook using for example Crossover then it's easy.
You need to follow the instructions from above.
I have myself macOS Big Sur and installed MT4 windows version on Crossover so I can use this 1415 .exe file from above to reinstall my MT4 back to 1415 version.