N diploma for Electrical have not received since 2018 February

Hello my name is Adelaide Mokoena ,i went to Flavius Mareka TVET sasolburg college in 2012 i completed my N6 in Electrical Engineering ,i then worked as a trainee at ESKOM from 2013, then in 2015 i did my other training with eskom when i completed my inservice training i submitted in 2018 february 2018 ,in May 2018i went back to my school they said there IS nothing they can do but wait, i personally called department of education no one could really assist me their phone is always ringing ,i went back to my school in may for proof of completion still the manager wants the certificate as my contract is ending they cannot hire me ,i need to know what happened to my documents