The question of course is why did you try to enter the wrong password that many times? It warns you after a number of incorrect attempts that you have to wait an increasing amount of time until it eventually locks out. Once that's happened, the assumption is that this was not your device and as such iTunes will not help you. The Apple Store has a way of unlocking the phone if you can prove ownership and so on.
That 3u tool looks to be used for jailbreaking, but either way, follow whatever article/tutorial/video you found for that tool and see what happens. But you're really on your own with this.
l took it to the Apple store, and the assistant said they can unlock it, but l would lose everything on it and thats theres no way round that. l still find that hard to believe. its like forgetting the code for a new electronic lock on your new house with all your memorable things inside, and after 10 attempts it locks you out permanently, and only way to get in is to burn the whole house down to make a new empty one reappear.
the assistant advised me that l should bring receipt to show proof of purchase and they can reset the icloud account as well (currently logged in with an old account where pw's and emails are no longer available). As l now have an iphone 6s, that has icloud which is shared with my mbpr, is there a need to have an icloud account on the iphone 5s which is still disabled (as l find it quite emotionally difficult to reset it and lose all thats in it). Reason l am saying this about icloud may be just out of ignorance, the only function l use the icloud for is 'reminders' , eg can type it out on my mbpr and have it appear on my iphone 6s. are there any other uses, since l get a free 15GB (currently sufficient)from google photos, which backs up automatically photos / videos that l have taken with my iphone 6s, also have dropbox and google drive. so a need for icloud for my disabled iphone 5s? lastly and most important does anyone know of a way of getting unlocking this 'disabled' status , with all memorable things intact?