Refusing to assist for payment arrangement

I took a loan .Cant pay full instalment because of financial reason so made an arrangement and paid what was arranged .I now want to arrange again have sent many email to arrange with no reply. I get calls but no one talks back when I answer. Getting messages though that they will send tracers to my address home or work .What do I do if they don't reply. I did NOT sign any contract .Im willing to pay but cant full amount