The question is how hard is it to contribute something orginal as so much have been looked at by clever people.If you have something original to contribute, it will be published. There is some argument that alternative theories have a harder time getting attention.
Where did you publish it?It may help if you are already an expert in some branche of physics or mathematics which so far has NOT been used in string theory. Then you have a chance to be the first who applied this branche of physics/mathematics in string theory. In fact, this is how I have published my first papers on string theory.
Eur. Phys. J. C (I think the impact factor is about 3.5)Where did you publish it?