Sakhile Mcambi/Karen Olivier

My Name is Nombuso Ntshingila, I attended a case at Karen Oliver for a guy Named Sakhile Mcambi, this guy signed a legal binding contract to pay me on or before the 1st of every month and that he will pay me 10% more of the previous amount, None of this is happening, instead he is paying me whatever amount he feels like paying and when I contact Karen Oliver over the phone, she is always busy and I have e-mailed them regarding this matter and it seems like they are not attending to their e-mails because I have not eve received an e-mail acknowledging that they have received my e-mail... What steps should I take now... Sakhile Mcambi has changed his contact details and he has blocked me on his Facebook account