Question about home mortgage

I have had my home for about 10 years. I have had a mortgage for about 8 years (we took over for a friend and refinanced with my name on it). In 2008, I got an unsecured loan to pay off some old bills. When I did so, the local credit union ran my credit report and I got a copy of it. The amount that I still owed as shown on my report (for the house) was about 12000.00. This was in 2008. When I checked to see what the remaining balance on the home was earlier this year, I was told it was 34000.00. When I asked about the difference between what the credit report said and what they were telling me now, I was told that it was because they had split the loan in two and I had paid off one half and now I was working on the other half? I have never heard of such a thing. At the time I asked, I couldn't find the documentation to back up my claim, but now I have it (thanks to the credit union keeping good records). I would like to approach the bank and show them the report, but I do not want to look like a fool. Has anyone had a similar situation, or is this something that is not legal? I live in Illinois if that makes any difference.

I can tell you that the person that was paying on the mortgage before me had a loan for a semi-tractor at the same bank and she filed bankruptcy, including the semi (this was why the rush to get the house mortgage under my name). Is it possible that the bank is trying to stick me with the bill??

Any input is appreciated, and thank you. You are all wonderful.:)