More details would be good. Do you mean that you can't unlock the column lock or that the columns won't slide? And what brand is it? Some routers will build up fines inside the columns. I had a Hitachi M12V do that. I had to work on it moving back and forth a little bit until it released and all the fines dumped out. Many new routers that have been designed with table mounting ability have flexible covers on the columns.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.