After many phone calls to find out what was going on, I was told that there is no record of my payment and that without a receipt I was liable for the debt. The debt was paid to the "Ontario Ministry of Northern Affairs" office which is no longer open. I have been to the bank to try to get the cancelled check, but the check was from my mothers account and she passed away in 1995.  I have spoken to the Ministry of Finance Collections  manager and the manager of the collection agency assigned with no headway. 

Without proof of payment, I have resorted to looking at other options. This loan was through a program called "Ontario New Ventures", and I cannot find any information on limitations law from 1990. 

My credit report has a payment listed in March 20015, which is, of course, false. When I called the collection company and asked about this the lady became very defensive and said "It's not a payment reported' it's the date we got the file, and it's not stats barred because it's government"... I guess she knew what I was about to say. When I told her "if the debt was not paid it would have been stats barred long before 2004", she was downright rude. 

Once that was over, she offered to take half of the principal as a settlement. I told her that my next step was a lawyer, but I would pay that amount today if it avoids lawyer fees and the account comes off of my credit report immediately. I was put on hold and when she came back she said "We can do that if you make the payment today". When I asked for that in writing she made multiple excuses as to why she couldn't do that. I told her I would not pay before I get it in writing, and she said it wouldn't happen and I need to trust her. I laughed... said "Thank you, but no thank you" end of call. 

I really just want this off my credit report even if I have to pay it again. Any advice?

I will say this. If you have no proof that a payment was ever made on a specific date for a specific amount, and their records do not reflect it, You don't have a case for that argument to bear fruit.  There are thousands of cases brought before review and inquiries of he said she said and it is the same result. Unless you have proof.  

The Ontario government is hurting for cash, and the Ontario student loans program has a LOT of outstanding invoices. They, like any other creditor, will do whatever they can to hook or crook people. Sad, but if you look at the volume, desperate government do desperate things just like desperate people do desperate things. If they are doing something unjust or wrong to someone then you have to catch them. 

I can't advise or do anything for you unless you are a client, but it is important that you come to grasp with the reality of what I wrote above. 

Good luck!