Company holding my original documents and not allowing me to leav

After Graduation, I Wanted To Go Abroad For Further Studies But Was Not Sure Whether Or Not I Will Be Accepted. So, As A Safeguard, I Joined A Company. Now, I Have Been Accepted Into A University. The Problem Lies With The Fact That My Company Has Taken My Original Certificates. When they took our certificates they said that they will return it within a few days. They have not given any written acknowledgement as well. Also, When We Started Working, On The Second Day Of Our Work, They Asked Us To Sign A Document Saying They Needed Some Of Our Basic Information. This Part I Agree Was My Fault That I Did Not Read The Entire Document. It Had A Clause At The End Written In An Exceptionally Small Font That There Was A Contract For 6 Months To 1 Year. Now, There Were Three Other People Who Signed That Document And No One Knew That They Were Signing Up A Contract, As They Just Said They Needed Our Information And Mentioned Nothing About A Contract. Also, This Was When We Started Working And Not When They Actually Offered The Job. Now I Really Want To Pursue Higher Education But I Am Stuck. They Are Saying That They Will Not Allow Me To Leave Even After 6 Months, Though The Contract Says That The Minimum Period Is 6 Months. They, now are not giving me the contract that I signed to make a copy of it so that I can read through it properly. I have been trying to convince them to state a leave clause but they are not saying anything about it. Is There Anything That I Can Do? Thanks.