Capfin harassment

I'm going through a financial crisis at the moment. Capfin gave me over to a debt company and I have been harassed more than 7 times a day with phonecalls to my work place this has cause strain at work and also them telling my colleagues why they are calling. Who can I report this to because I've given them times to call but they don't, instead they call whenever they want when I'm not available. I've been trying to make payment arrangements but to no avail.