Payment after end of subscription

Hi,

I have had the hardest time reaching you through different means. I moved recently and had to cancel my subscription. When the invoice arrived, I paid through direct deposit (which was an option you offered) adding my client number as instructed. Not only I am still receiving a reminder from you, but now the insurance company that offered me a policy through you when I got my phone has contacted a collector to get that money from me (I have paid that invoice too, along with the main amount, as I have always done). They are insanely unresponsive to emails/calls, etc., but the main issue should be resolved through you! During two years I have paid my invoices on time, it’s crazy that now I have to deal with this (especially since I have paid already). Please let me know how to solve this issue. 

JC