North Shore Agency, Inc. - NSA nsa sent me a bill for $51.48 for the us weekly magazine subscription that i never got and do not want westbury, New York

i have received a bill from north shore agency, inc for the amount of $51.48 . the letter states that it concerns my subscription with their client US WEEKLY. that since i did not respond to previous letters that US WEEKLY asked north shore agency to contact me. they have given me two oppurtunities to either settle the account and pay the balance or reinstate my subscription to US WEEKLY and to receive  the remaining issuesin my original subscription. first of all i never subscribed to this magazine nor did i ever receive a single magazine. i do not wish to subscribe at any given time now nor in the future. the is absolutelty bologna and they are ruining my credit. i need this matter taken care of before it does any further damage to my credit.  i hope you can assist me in this matter.