Request for legal assistance

I have a SUB-CONTRACT with a Courier Company Blue Express in Bloemfontein, on 2024-10-11 my vehicle was involved in an accident and a crew member passed away... The contract gets paid on the 10th of every month but this time it was not paid even the deceased person's Monies was not yet paid... The contractor Blue Express is ignoring my calls and refused me entry into his premises.. Where can I start to file breach of contract lawsuit?

Regards Ms Mosibi My email address is *** and contacts are ***