Absolutely not the case. You can change officer recruiters, and in some cases, you absolutely should. Like all professions, there are those that take their jobs seriously, and there are those that don't. If you are being yanked around by someone who does not take you seriously, call the Officer Programs Officer, explain the issues dispassionately and professionally, and ask for input. If nothing happens, call again and request a new officer recruiter. Each time the situation is not resolved, go up the chain of command, XO, then CO.
Not to say this should happen very often, or that I advocate a tattle-tale mentality. This process should only be used if the situation seems to warrant it (your OR goes weeks or months without contacting you, even you call/email consistently, or the OR seems always disorganised and doesn't seem to remember where you are in the process, multiple missed boards for no seeming reason, disparaging comments about your chances etc...).
In a way this is true, in a way it isn't. If possible, I know at least one NRD CO that advocates asking for a commissioned officer recruiter, especially if you are having trouble working with someone already. This is very often because the commissioned officers have been through the same process, I know my new OR had the same trouble with his officer recruiter, and became an officer recruiter to help others get through the process. The commissioned ORs have been through the process and through OCS. No matter how experienced a perspective an enlisted officer recruiter has, it is inherently fundamentally different from the perspective of a commissioned officer- a person who embodies your goal.