Q.Weeds totally overcame my wildflowers
Working through a local landscaper we put in a 1/4 acre wild flower garden. The first year we have wonderful poppies, and then some wildflowers into mid summer. The second year we had grasses and weeds taking over, and the third year, even though the landscaper sprayed Round-up 3 times after letting things sprout in the fall and very early spring, the weeds have totally over run the wildflowers. Should we roto-till and rake off roots perhaps? Should we put in top soil? Any suggestions would be appreciated.

A wild flower garden, by definition, is composed of flowers that grow wild in your area - in other words, they are...weeds! Wild flower gardening is gardening in which you let things do what they do, rather than trying to force a preconceived design. This article might give you some more ideas: https://www.gardeningknowhow.com/special/spaces/a-wildflower-garden-in-your-backyard.htm
I think I would not use herbicide, because it's probably killing as many of your wild flowers as it kills weeds. Rather, simply pull out some weeds and plant more seeds. If you keep trying different seed mixtures, eventually you'll find those that do well in your spot, and can coexist with the other weeds. You might also try to find someone who's more of a specialist in wildflower plantings; you can also access the county extension service to see what advice they have. This link will help you locate the nearest one:
https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm