When you drill down to transactions of receipts and payment, the sequence of reference numbers is not in order anymore. Has something changed?
Can you explain further? When opening the Receipts & Payments tab, the default display is in order of date (most recent first), then reference (if any). If your references were not chronological, you can clicking on that heading to reorder by reference number.
If you are referring to some other view or page, there may be a different ordering.