Your concerns are understandable. You obviously need guidance and support from the counsellor throughout this major step of joining an MBA program. If you feel that your counsellor hasn't provided the help that was promised to you, your best first step is to contact the university directly via its admissions office or student support team. They typically have people dedicated to addressing such concerns, and they'll be able to put you in touch with a person who can assist you with either academic or professional career guidance.
Another good idea would be to keep records of your conversations back and forth with your counsellor to create a detailed list of what you expected from them and what you didn't receive. In most universities there are grievance systems set up so students can formally raise concerns and hold the university accountable for their actions. Additionally, there are also other resources available to you once you are on campus, like mentor faculty members, placement offices, or peer groups that may be very helpful in supporting you.
The MBA journey is about much more than your counsellor. It is your responsibility to take advantage of everything at your disposal for assistance throughout your time in the program. For example, networking with fellow students, attending seminars, and making connections with professionals within your desired field will all provide you with additional guidance. Taking the initiative to seek out opportunities will allow you to maximise your time in the programme.