Speed services couriers is a **** of a company

I will never use speed services couriers in my life again. I got a job in a certain company in limpopo, my qualifications were kept in my institution due to outstanding balances in my name. Luckily I manage to pay up my balance for them to release my certificate. I had to ask my younger brother to fetch the certificate and send it to me since I was in limpopo already. I gave him money to courier it via speed services overnight courier because it was need in the company by Friday the 7th of August. For me ti be on the safe side I asked him to send the document on Monday but surprisingly even today the documents have never reached its destination. From Tuesday I've been trying to get hold of their offices but I can't. The company had to terminate the apointment because I failed to provide the qualification in time, all thanks to post office speed services couriers. I asked them to atleast give me back the documents so I use another couriers but that was not posible to them either. I really don't know what to do now, maybe it's best I try some advise from my lawyers that's my last option in mind now