Can anyone help,

Recently changed my phone provider, got supposedly a new number. In this last week I've been getting loads of nuisance calls, person is not clever enough to withhold number. I've contacted my provider and they reckon all they can do is 'maybe' trace our line to see when we get the calls. I've rung the 'mystery' caller number myself and left a message on the answer phone, call diverted me straight there. Police say go into station and fill out their forms and they'll monitor line for 28 days.
Will I get anywhere if I contact 'mystery' callers provider myself?

Regards,
Steve


(soory if posted in wrong place)