Is it ok for a Consumer Financial Service/Sales Finance to be doing business as company not registered with Office of financial regulations?

As a general matter, it is lawful for businesses to conduct their operations under an assumed or fictitious name, as long as the name isn't misleading. In this case, if there is a lawful, licensed business and a reasonable consumer would not be misled regarding their identity, I don't see a problem. If you have somehow suffered harm because you were confused into believing that this lender was someone else, it is possible that you may have a claim. If so, you should consult an attorney.