Redemption VW Bank Financing UPP

Hello to all of you I have now spent about 30min in the SUFU but found nothing also entered everything possible if there is a thread please write in. I ordered a new Passat CC and received it in August. I did this via the scrapping premium. The car was financed with the VW environmental premium plus with 2.9%. The financing runs on 4 years I want to pay off it of course earlier Where I have bought offers the sellers said you can n after 6 months completely pay off or also make partial payments. Where the car bought from the seller who does not work there anymore. In case of a demand for the redemption in the car dealership they told me the interest will not be charged at a partial redemption and I should invest the money where differently there hba more of it. But this was confirmed to me then by several sellers that it goes with the partial redemption. Since now in February 6 months I wanted to pay in immediately 500€ It would be really great if someone could help me and of course thanks in advance! Greetings Robert edit: Have you ever heard that there is a processing fee at the VW Bank as well? Is it possible for me to pay a fee for the payment of a fee for the payment of a fee?