It would have been nice if you had been a bit more specific. What surfaces? Why can’t you deal with them? You say you want to “fix” your model. What is it you think needs fixing?
As it happens, there are a bunch of things wrong with it, mostly attributable to careless modeling.
For one thing, you saved the model upside down; that is, with the solid Blue axis down and the dotted Blue axis up.
For another, you can’t have multiple or nested groups or components in a solid. The Group or component recognized as solid is only one level deep and contains all the geometry making up the solid.
For another, most of your faces are inverted. All the faces you see should be white, all the blue faces should face the interior of the solid.
The construction is not symmetrical where it obviously was intended to be. You should have modeled half and flipped it for the other half.
Most of your tangents are not smooth.
Please be more specific about what you need help with.