If you won't be able to produce your category certificate then you will be treated as a General candidate. So you have nothing to worry about. As you have done some mistakes regarding this which is not that much of fatal. There can be problem, if you get a job due to your OBC quota then you will not get the job. Apart from this there will be no problem if you get job in open quota.

To know more about SSC MTS visit the link below:

https://competition.careers360.com/articles/ssc-mts

I hope this answer helps. All the very best for your future endeavors!