worst service ever

worst insurance ever, in 2015 i cancelled my policy to move to another service provider, i have email confirmation that the policy (on policy number) was cancelled as requested. in June 2019 i receive an email stating that my policy is due to increase, shocked i called them to find out what this was!!! turns out it is a VAP (value added product) on same policy number. after 4 years of no correspondence from them i realise that they have been debiting my account every month and requested a refund. despite having written confirmation that my policy was cancelled in November of 2015 they refuse to refund that money as the VAP was not cancelled seperately, even though it is on the EXACT SAME POLICY NUMBER. not only that, they never call or email back and then send me sms messages to call them!!! i just want the money back that they took every month, on the confirmation of cancellation no mention was made of the VAP. who do i contact regarding this as their call centre people are "all in training"?????