Wasn't me....

So I had a minor repair to a door panel on a VW Caddy. After the repair everything looked and worked ok, but after the first day I was unable to open the door from the outside. Was never a problem before the repair. I went back to VW and asked them to please have a look. They bluntly dismissed it as something unrelated to their work. Not a problem before their repair but now it is a problem....what can I do. I'm sure this is a 5 minute job to make right but they'd rather not offer that as I would to any of my customers.