If you refuse to cooperate with CPS and if they feel the child/children are in danger of abuse or neglect, they can file a petition with the court asking that your children be temporarily placed in their custody. It is better to cooperate with CPS and work whatever plan they develop such as counseling, anger management , random drug testing, parenting classes, etc. If you feel that they are abusing their position you should get a lawyer familiar with CPS issue.
I agree with Mr. Martin. In terms of "services", CPS does not just bundle them up and drop them at your doorstep. You have to go get them. Services can include counseling, classes, etc.
If you don't agree to a safety plan, they may refer your case to the DA while may then sue you to take your children from you. On the other hand, you don't always have to agree with their exact safety plan. The plans can be negotiated. Doing so without an attorney is very difficult.