Unable to cancel month to month contract router.

I bought a month and month router 300GB last year December online via Mundo and then this year in August i upgraded my router to 500GB. I requested MTN to cancel 300GB several times and even sent multiply emails to cancel. No one has assisted me to this day. MTN is has been charging me for two router for 2 months even though i am only using one. When you call you get transferred from pillar to post. Feels like modern day ******ion