You've been adding and editing records directly in your table(s)? Not the best idea.
Did you try the form wizard and see what it creates for a form if you base it on this table? I don't know if that would be of much help because I'm not sure if your comment means there is only one table in this entire db. If that is the case, you're making things more difficult for sure. Without a form, you really have no chance to do something like copy several fields from one record to another (or even just one if that one is the customer field).
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.