Outstanding balance

I currently owe Monash varsity fees for first year. I have discussed my situation with them and we came to an agreement that when i am able to pay them back I will as was not currently working at the time. They have one of my certificates for a course that i have completed and already paid for but they refuse to give it to me. Now they have sent my details to their lawyers. Even though i have explained the situation to them and have given them the documention that they requested(ID, bank statement, affidavit of unemployment ), they continue to harass me via email.