You can call and/or contact Samsung on their website, tell them that you would like a quote to urgently book the very next available appointment at the nearest repair/service centre , explain that you would like to factory reset your phone because you can longer access it due to some unforeseen circumstances (Eg: Your kid/elderly relative accidentally changed the passcode while they were on your phone and are unable to tell you the pin, Eg: you accidentally deleted an essential file/folder, Eg: No longer have access to recovery methods... Etcetera), tell them that you have the box; proof of ownership; and ID to prove that you are indeed the registered owner of the device. If you are on a pay monthly then alternatively conract your contract provider as they may offer a similar service.
It could also be the perfect excuse to get an MOT for your device, or potentially the perfect excuse to get a replacement/different phone.
If you are using your Samsung account on the device itself, it should have automatically backed this up to the cloud... If you don't know, whilst you are at the appointment, ask the Samsung engineer if they can restore your data.
Please let us know how you get on or need clarification. I truly hope I was somewhat of a help to and, hopefully, by the time you read this, you will have resolved the situation!
Kind Regards
Jack
