I have a major problem on a family loan?

I took out a loan with my sister on a house we own together. The loan was for $ 40,000.00 on a 6 % interest for 10 years. My part of the loan was $ 9199.00 ( credit debt) she added $ 2500.00 for interest and I paid all of that in 3 and a half years. She is now telling me I still owe her money because its a ten year loan. My question do I still owe her money? I feel I over paid
both of our names are on the mortgage…I only pay her rent because I live in the apartment in the house.
Believe me she will pay whats due she will no let this house foreclose