If it is true that you stole, they may do this. If it is not true, then saying you stole would very likely be defamation, since it would be a false factual statement which damages your reputation and/or makes others less likely to work with or do business with you. (True facts are not defamation.) Being cleared of the charge does not automatically mean that they may not call you a thief, since the standard of proof in a civil case, such as a defamation lawsuit, is less--e.g. if you sue them for defamation, it is possible they could show it to a sufficient level to raise the truth as a defense. However, it is still obviously powerful evidence on your behalf that you were cleared; therefore, from what  you write, you may be being defamed, and you should consult with a personal injury attorney to explore your rights and options. Good luck.