Assignment submission error

I submitted my assignment on the 30th April before the extensions due date. Mancosa says that I did not submit and the onus is on be to submit on time. I informed them that I do not receive any submission emails when submitting. They informed me that they migrated from mymancosa to MANCOSAConnect thus the reason for no submission emails. I logded a urgent query with them via email, ticket #426438 but to date no one called me as I requested they investigate with their IT department if an error could have occurred. I even emailed them my assignment which I submitted and my other assignment marks. Mancosa, I am not a first year student, please don't treat me as a delinquent. I do not have time to play with my studies as this is not my first degree. This is my first time studying with you and if this is the treatment I receive, it will definitely be the last.