Santu,
The top bschools are looking for genuine candidates with credible stories & accomplishments. However, in the desperate race to get into a good school, candidates (either independently or with consultants) resort to unethical methods that can have serious implications.
Read why
UCLA Anderson rejected over 50 MBA applications in the last season.
If you can't find a good and affordable consultant (as with any other service, word-of-mouth referrals work best), then the best approach is to manage the application on your own and then get those apps reviewed by someone you can trust, before you submit them.
A few options that you could consider:
1. Check out the
Free essay review service offered by GMAT Club.
2. Reach out to current students or alumni of schools that you are interested in. They might be able to give you perspectives for their alma mater that are available on the official websites.
3. Get a few trust-worthy colleagues (who are familiar with international MBA application processes) to review your essays.
4. Ditto for interview practice. Get a few mock-interviews done before D-day.
There are pros and cons of the approach. But all this can be done for free and 100% of the content is your own (as opposed to being re-used from other applications). Plus, as you are working with knowledgeable folks you trust, the chances of drifting into the grey zone is reduced.
Good luck, buddy.