It is not a crime to apply for a suitable post in any of the company regardless of whether you have applied earlier.
If this time, your graduation degree is valid and your MBA institute is recognized, you may reapply for the post.
There is no need to hide the Diploma matter. Whether an institute is recognized or not, you have earned a diploma.
It would be unethical on your part to hide this. if they somehow find out, then there would be terrible consequences for you.
May be you can write a good cover letter to your application of job stating your positive points, etc.
Simultaneously look for other job opportunities
best of luck
11th June 2015 From India, Delhi