Most of the times it happens that a Developer comes to know about Code, database, or Project related complexity only when he gets the code details. Client provides the Code details only after starting the Contract.
Once a Developer check the existing code or database, and found he would not be able to complete the job, then in that case he close the Contract, and refund all the Milestone Payment to Client. That is Developer close the contract without any type of Payment on the same day when the contract was started.
As here it was not the fault of the Programmer, so that non paid contract should not be considered in the Job success score calculation.
So please think once agin on the Job success score calculation, so those contract can be avoid on which Payment was not made.
There are times when you will come accross something in our field that is so complex and seems impossible to do but the client is demanding it, it happens all the time with me......but the reality is its all on your head, your the professional here not the client, its your responsibility to either inform the client that this impossible thing is really not possible and offer an alternative or open google and study, goto forums and ask for advice, inform the client you need a little time to figure it out (im sure they will understand after all they already INVESTED in you).
Now if we take it back a little bit, you should have had the project details before you even accepted the job, taking a job just because your thinking about the payout is a bad idea (not saying you did) if you know you cant do something at least you can inform the client beforehand and maybe something can be figured out later and you still get the job........its just unprofessional to just be ignorant and in the end you actually damaged everyones prospects in our field as this client will likely be so stressed right now hes having second thoughts about coming back (it happens but you should be aware and minimize this).
Do i think Upwork should include this in your profile yes i do, but not in the way you think...... you failed your job, possibly lost a client, cost Upwork alot of money (yes Upwork also pays for YOUR lost contract) and because Upwork is paying for your mistake its possible that the rest of the freelancers may be asked for extra fees because Upwork cannot earn enough money to function properly..........
I would just accept where you are now get back to work and try and fix your situation and learn from this mistake....
I dont mean to sound blunt, and im not trying to make you feel bad im just pointing out the facts of what just happened and not to expect upwork to give you something possitive for this.