that is why you want to make copies of everything. now you have to go back to the place where you took the class and get more copies of things you already turned in. usually, when someone completes a required class, the probation officer will make a note of it, somewhere. Get an aggressive attorney to represent you, do not think you can save money on an attorney, when your freedom lies in the potential balance.
If you cannot afford an attorney you can request that one be appointed for you. He or she can seek a dismissal of the violation of probation and a termination of probation on the basis that you submitted all of the documents timely.
Punishment for violations like yours varies depending on what part of the state you're in. In North Florida cases are often dealt with more severely. However, if you have all your documentation I think the judge may terminate your probation.
Every case and situation is different and vary greatly depending on specific facts. My posts are not to be considered complete answers to each question. My posts do not constitute an attorney/client relationship.
I would not recommend going without a lawyer in this case. If you cannot afford one, ask the judge to appoint a public defender to represent you. While this matter may be cleared up by showing proof of completion and that probation may have lost the paperwork, it's much better to have a lawyer give the explanation. Many times people in similar situations can find themselves in worse ones without hiring a lawyer. Most judges are understanding of the situation you are in, and it is not an unusual one, but sometimes, there are nuances in a case that can make can change a judge's opinion, and lawyer would be more sensitive to that than someone representing themselves. If all is as you say it is, then I doubt you have to worry about jail time, but you need to get a lawyer to review the case fully before you can feel safe about that.