Paid off my account but still billing

i had a contract with Nashua Mobile in 2009 and i paid off the account in 2012, We agreed that the account must be closed ,<br> <br> In 2014 May i received a call from call centre said i am awing , i explained to a lady that my is closed , otherwise they send me all statement from 2011 till 2014,<br> I received nothing , no phone call no sms till 03/12/2015 i receive an sms saying my account is handed over <br> <br> Nashua close my account , check all my statement i owe u nothing and i am sure you wont get a cent from me because i owe you nothing .<br> <br> I need everything under my name from Nashua to be cancelled, Close my account