A definite cold call from someone claiming to be from "smart tech energy". "We're currently in your area...". I tried my latest tactic - "oh thank you; what area is that?". He replied with the first half of my postcode, so clearly has some data on me. I replied "you've called many times before, and we've asked you to take us off your list. Please can you not call again". He replied saying he could see on his list that he hadn't called, then put the phone down. We get frequent calls asking us to have our solar panels serviced (a common tactic, whereby someone will visit and then find a non-existent fault, or try to sell you a battery), so I think the call related to this, but I didn't get that far to find out!