Regain data from iphone 6s(not sure if plus) factory reset?
If you have not done a backup either to iTunes or to iCloud, then there aren't any ways to do retrieve that information. It is an Apple security mechanism. Hypothetically, let's say someone stole your phone, tried to guess your password over and over, it would disable it. There are programs to access a lower level of the phone, but they require it to be unlocked. The only thing I can think of is using major data recovery, like through DriveSavers or Kroll Ontrack recovery services. They're quite expensive though. It'd recommend attempting to restore from your most recent iCloud backup. It won't hurt. 

Unfortunately, if that doesn't work, you will have to restore your phone, and there won't be a way to get that information back.