To ''act without your approval'' could mean he's going to fold paper airplanes or count the sugar packets in the collection office break room. Of course you're meant to imagine you are a step away from getting sued, much like the ''case number'' line heard by BeenHereBefore.
Whether you are called a debtor or some collector thinks you can flush one out, you have rights and options. Most are simple to exercise if you only learn how. The FTC and the CFPB can start you on your homework. See also if your state laws grant additional or stronger rights.
official FTC guidance and staff opinions on the FDCPA, PDF copy of the Act
CFPB reiteration of the Fair Debt Collection Practices Act