Ronnie mate, assuming the worst and all data is lost you have to start somewhere right?
First you need to compile a list of clients as best as you can.
Your bank statements is as good a place to start as any. You will have a good idea when the job was last done, check out on your statements any payment received.
I don't know if your bank can help with names on cheques received, but you could try, they will probably charge of course.
I do log any cheques or online payments in a book that I carry with me on the round.
This helps out if there is any dispute about payment either by cheque or online.
cash payment is a difficult one, if your anything like me you will have entered these on paper, book or round card at the time of payment, but if you only record these on your laptop in the van, O.M.G.
Ron, you have been in the game long enough to know that many people will try and pull a stroke if they think they can get away with it.
You need to sit down with your staff and get your memories into gear.
If you go through the list as you do the round, try and remember if they paid or not. Some if not most payments will be remembered.
If you can't remember right now, it may well come back to you when you are next doing that job.
If your not sure, bill them for last time too, they will soon tell you if you are wrong.
You can then apologise and explain what's happened.
I have slipped up in the past through talking too much, and forgetting to mark my round card as paid or out. Next time round I ask,"did I miss you last time"? as I fumble in my pocket for the round card. If they didn't pay they usually say yes, before they are confronted with the recorded non payment.
If they say "no I paid you", you can say "so you did" as you look at your round
card, "it's the one down the road I missed".
I hope this helps mate, but your round is massive compared to mine.
Good luck mate, I see you have offered a reward, I'm sure most of us will agree, the only reward we want is to see these bastads banged up.