I called back number (07) 3613 6267 reached voice mail but did not say for what company.

Might be worth trying Apple Marketing. They work for various charities, major part of their work seems to be verifying phone numbers that are typically answered, during certain time windows. These lists are supplied to the charities for their fund-raising calls. You can ask Apple to add you to their own internal "do not call" list. That should knock off a number of the calls. Check their website. The number of unwanted calls seemed to have decreased since I got onto their DNC list but sadly have been receiving persistent calls in recent days. I never answer the landline now unless I know the caller. Any genuine caller will leave a message.

Email this address and asked to be removed from their calling list callingenquiries @ paretophone.com

keep ringing but hang up if you answered. highly annoying

how do they bypass the do not call register

I called back number (07) 3613 6267 reached voice mail for a charity company but did not say the name.

keeps calling and hangs up when answered. I don't know this number!