being harressed for payment

i have received numerous calls stating that we as a company still ow Linkqage money on goods that we bought in early 2000's, we have always been a COD client and lately we are being harresed with money they claim is outstanding since then, we have always and still make use of their services on a COD fashion but this is now getting out of hand as its sitting on there books that we ow a sum of money and we reflect as a bad payer, i would like someone to get back to me and this matter being resolved and our name being cleared.