I realise now that we got two of these calls today but my first thought was that this was telemarketing and I always try to let them down gently. It's like shouting at the waitress when the chef is at fault and I try hard not to do it; they're just doing a thankless job at the frontline. Anyway, the first call asked for my mother by name so I said that she was deceased and that maybe I could help instead. He then asked about our PC and I explained that the only one was my business PC, completely separate situation and nothing to do with the household. I told him that we didn't need whatever they were offering and thank you, goodbye.
The second call, asking for my father this time, caught me at lunchtime, up to high doh chasing my own tail so I was a bit more impatient. I told him that I'd already explained to his colleague earlier about not needing their service (whatever it was because I didn't give then time to launch either time) and would he please ensure that we were never called again. He promised me faithfully that he'd see to it and he sounded like such a nice young man that I'm sure I can count on him to keep his word!