Yes, your children can now be taken away. A refusal to cooperate is considered automatic guilt by DCF. A refusal to take the drug test is considered a failure of the drug test. When DCF receives multiple calls which result in "unfounded" (dismissed) allegations, they take the calls less seriously, but you don't get to decide for them when they should stop investigating. You now need to hire a lawyer. Now.
The contents of this answer should be considered friendly advice, not legal advice (I'm a pretty friendly guy), and the answer should not be construed to constitute an attorney-client relationship. If you'd like actual legal advice, call me for a free consultation at 813-635-0222. Also, if you liked this answer as much as my big ego thinks you did, be sure to click the thumbs-up button!
Yes your children can be taken away. You are in a very serious situation and should contact an attorney in your area directly to assist you and make sure you are in compliance.
You should consult an attorney for advice regarding your individual situation since every case is different and not all information is relayed in an online question. The Law Office of Ophelia Bernal-Mora, P.A. is a family & criminal law firm located in Orlando, Florida, we invite you to contact us and welcome your calls at 407-377-6828. Contacting us does not create an attorney-client relationship. Please do not send any confidential information to us until such time as an attorney-client relationship has been established.