This was reviewed directly by the owner of the company, not one of Taxi's screeners. So the library owner felt it wasn't a fit for his/her needs. At least you got it heard directly by the Taxi client... That's always good!
If you think the tracks are solid, keep submitting to other listings, libraries, etc. One option is to get a Taxi custom critique and ask specific questions relating to these reasons for return.
Best of luck!