Dishonest Agents

I have called to cancel my contract due to immigration (You can ONLY call). The agent moved me onto a whatsapp only bundle and assured me that end of December would be the final payment and then it would move to prepaid. This is not the case as I see there is no cancellation on my number. I also requested a cancellation quote for another number which I never received. I refuse to pay again for his incompetance.