The telephone operator tries to gain your confidence by mentioning they've helped you in the past with your energy contract and want to make you a new proposal. By challenging them that they have helped me in the past, the tone of the conversation changes and the operator chose the aggressive strategy by mentioning (with Dutch accent): "nou dan kan je lekker duurdere energie betalen".
These practices are outrages and it's really time the policy makers restrict this way of scamming or selling co