Don't do business with them is a bogus missive, but you could lock your credit with all the agencies and only unlock the agencies you care to do business with when requested. But that often makes things difficult and not all users of that data will have an account with an alternative provider. (nor is the locked access the only product for which your data is offered...)
You could make sure you put on all loan applications that they will not check Equifax. Probably they won't even know how to handle that though and will either reject you, or ignore it.