Are they tightened down? Is it shifting from recoil? I don't like see thru's but know some guys who use them and although they may not hold zero year to year they don't shift from shooting a few times. I would take them back and explain to the guys they just don't work, then get some post mounts...weaver at least! I assume you have irons as well use them unless you have time before season. You can try tightening them and using some blue loctite on the screw to see if that stops the shifting. I find it hard to believe they are not holding the scope in, unless they are not meant for your scope or the diameter tube...if that is the case you should be able to return them and get your cashola back.

My first course of action would be try and return or exchange them. Then try loctite and retightening or take your gun to this gunsmith to see if he can help you out with the setup for this year anyway. Go with a good base and ring combo by burris or leupold. (if you can make it work for this year and then move upto a better setup when money isn't as tight)