Stop Unwanted Robocalls and Texts
Unwanted calls – including illegal and spoofed robocalls - are the FCC's top consumer complaint and our top consumer protection priority. These include complaints from consumers whose numbers are being spoofed or whose calls are being mistakenly blocked or labeled as a possible scam call by a robocall blocking app or…

01218200639 Phoned our mobile. We then received 6 more calls, all from different numbers in the period of a couple of hours. All silent calls.
Useful report sites, ICO https://ico.org.uk/make-a-complaint/nuisance-calls-and-messages/ Ofcom https://www.ofcom.org.uk/phones-telecoms-and-internet/advice-for-consumers/problems/tackling-nuisance-calls-and-messages/abandoned-and-silent-calls