"Poff" it is illegal for a debt collector to call you at work. All you have to do is give a verbal warning on the phone that you cannot receive personal calls at work. Hunt & Henriques will tell you *any* lie they can to make you think they will. They will threaten all kinds of things.
Send a simple USPS certified mail to them with the following,
"I dispute your claim. All calls to my home, place of employment, family or friends are inconvenient. You do not have authorization to call my cellphone."
This will force Hunt & Henriques under the law to prove their claim. It will also give you protections under the FDCPA. Google FDCPA, Debtorboards.com and creditinfocenter.com. If you inform yourself, you will beat these scumbags.
Add the following to the language above (after the sentence about disputing the debt). "As such, kindly provide verification of said debt, and kindly do not contact me again until you have provided me with said verification".
If you send a dispute/verification letter that says you dispute the debt and request verification, per the law, they cannot call or contact you again until they have provided proof of the debt. Most of the times the debt has been sold again and again and the collector does not have legit proof of the debt, and as such, they have to leave you alone. Now you could just "dispute the debt" and tell them to pound sand without requesting the "verification", but you're probably going to want to know whether they have proof and can later sue you. The request for verification requires them to provide proof. Note, if they do have proof and the debt is legit, you can still settle it for way less than the original amount (keep in mind that they pay literally pennies on the dollar for your debt). Or, you can still dispute the debt after they've provided verification, tell them not to contact you at all, and they will have to, per the law, leave you alone or file a lawsuit. They are not allowed to keep calling you and writing you after you've disputed the debt and instructed them not to contact you.
Also, if you do return their calls, for the love of God, don't give these idiots any personal info about yourself other than your name and the phone number they have already called.