Land line, in my case.
I have occasionally received nuisance calls on my mobile, such as PPI reclaims agencies, or car dealers touting for business. But I don’t recall ever recall receiving a call on my mobile that was an outright, illegal, scam.
I attribute that, rightly or wrongly, to the idea that whilst all calls can be made at very little cost, calls to mobile are not quite as cheap as calls to landlines. For a scammer aiming to make 1,000,000 calls in the hope that 100 succeed, the cost of calling mobiles may possibly be too much.