My employer promised to sponsor me for Green Card and has now withdrawn that offer. I am a Speech Pathologist

I am licensed in Florida and have my CCCs from ASHA. They have sponsored me for H1b and a week after I returned from London with the Temporary Visa, they called me into the office to tell me that I am not qualifed for Green Card Sponsorship! Are they allowed to do this? http://bit.ly/qCI6G1