Ambermile is spot on with the problems you are having - my brother has the same scope. With regard to what you have been sold, is it the scope or the t-mount and adapter that you think you were mis-sold?
If, when buying the scope, you indicated that you wanted to use it for astrophotography, and the salesman recommended the Astromaster, then you have a case. Likewise with the adapter - if you told the salesman that you wanted to use the parts to enable you to take photographs through your specific scope, then if he was on the ball he should have been able to advise that it wouldn't be possible.
If however, you merely stated that you wanted an adapter that would allow you to connect your camera to a telescope, then that is what you have got; the problem is that whilst they will work with a different scope, they don't work with yours. Don't think you will be able to get a refund if this is the scenario you went through.