Ha ha ha ha ha Oh i am sooooo going to do that!!!

Hi all, First time poster looking for some advice. For the past 2 months i have received approx. 50 phonecalls from DLC asking to speak to my boyfriend. At first i was polite & informed them that he works until 7pm & that if they phoned back after then they would get to speak to him...no one ever does. Now i am just losing my temper! Is this harrassment? The only debt they can be chasing is over 7years old, is this now classed as statute bar? My boyfriend has managed to speak to them once, they have said that he made a payment last year of 97p which we know isnt right. I mean who would bother to pay 97p?!? We've asked for a detailed letter to be sent out, all they send is a letter saying 'call urgently & quote ref. number ....' They havent told us who they bought the debt from, what the debt is, nothing. How do they expect us to deal with them if they wont tell us anything? We also asked for them to tell us how the 97p was paid, where it was paid etc.. but again they havent. When the did speak to my boyfriend he refused to give any personal details to them as we've had problems in the past with data fraud from Brighthouse (aka ****ehouse....long story!) I am now at the end of my tether. How can i get the phonecalls to stop? Or at the very least get them to send a letter explaining everything we need to know? Any help would be great