set crossover point and slope on an ARC EC21

I have an ARC EC21 crossover and want to reconfigure the crossover point and slope. ARC would not perform this service for me. First time (in almost forty years)I have not been happy with my ARC gear and the company. Anybody know a quality service person near Minneapolis Saint Paul Minnesota?
You could try Dave at Hifi Sound in Mpls.
HiFi Sound did some repairs for me years ago. I'll give them a call tomorrow. Thanks,
Well, that didn't work. Dave said Hi Fi Sound doesn't sell or support ARC. Hmmm, anybody got ideas?