Acccount received for cancelled contract

I cancelled my Nashua Mobile contract last year for the end of November 2014. <br> <br> In February I received an account from MTN for the same cellphone number. After being pushed from pillar to post by MTN and Nashua, I finally managed to get the proof of termination from Nashua. I am still being billed for an account that I cancelled. MTN say that I must sort this out with Nashua Mobile (who have closed their mobile division) and Nashua say that I must sort this out with MTN.<br> <br> The service from MTN is ridiculous. I cannot be expected to pay for a contract that I did not agree to and cancelled with Nashua Mobile in June already.<br> <br> This is *******. I expect feedback today!