May of used up whatever was left in the battery. That's a shame, as was going to suggest trying the 'wipe cache partition' option from that same recovery menu. I'm not sure how much that would help though, considering you've done a factory reset, but it was worth a try.
I've seen instances where the thing just decides to take a charge, sometimes weeks after previous failed attempts. So I'm reluctant to advise you to just chuck it in the bin.
I think at this point, if no one else is following this thread and can offer any other suggestions, then your only options are
● Inspection and repair by authorised Samsung centre. This will incur a cost to you.
● Approach Sky and complain.
● Leave it for a week or two and try charging it again.
