Our first priority has always been to make sure that a member is properly reimbursed for a legitimate, church expense. When someone has lost a receipt they sometimes have the attitude that "it's not a big expense so I'll just 'donate' what I paid and we'll forget about reimbursement." Of course, that distorts the record which would otherwise show what the real budget should be (if it's a budget expense). So when all else fails, I would gladly accept a member-written "receipt" to file with the paperwork. It's pretty easy to find witnesses (including a member of the Bishopric) to tell us that, yes, there was ice cream at the youth activity so, yes, someone must have bought it.
When we talk about "invoices" then we're usually referring to a good or service that wasn't purchased at a regular store. If, for example, a plumber repaired something for a fast offering recipient, then a professional plumber should be accustomed to producing invoices. So, for the sake of this topic, are we talking about someone who provides goods or services "on occasion" and doesn't have a habit of producing invoices for their work? I'm just saying that anyone who expects to get paid should be able to produce an invoice and should also be able to produce a copy if the original was lost. Why can't this person print out an invoice?
My real name is Greg Anderson.