Right. That's not exactly how things gets quoted at the recovery process/service but I take it everybody needs to make a living.
First-thing-first, see if you can find an electrical engineer locally to look at the chipsets/datasheet and diagnose what could have gone wrong. Most likely the firmware was corrupted and this can simply be re-flashed using a spi programmer. You are looking at 200~300 labor max (reasonably paid). All of my SSD failures (two only, mind you) were a re-flash case. e.g. copy the hex table from a good drive, then burn it over to the faulty one and whala. Which is most likely what that 24hrs service is all about (restoring large amount of data byte-by-byte takes a whole lot more than 24hrs ).
Correct on the reliability of SSDs vs Discs. SSD needs a fairly stable power source to perform properly, slight fault in the power rail and bang goes the firmware (corruption, in most cases). Disc drives can't be used in a vibrating environment so good thing you've got rid of that.
ps: your local mobile phone repair dude is able to carry out the 'diagnostic' part for you. He/she knows how to read mfg datasheets. Whether you let him/her do the repair is your call. There is a risk, obviously.