dell computer dell Late charge assessment fee AUSTIN Texas

when i received my dellm preferred account stetement they imposed  a late charge assesssment fee of 14.00 now i have to pay 66.00 monthly its  not right and unfair usually i mailed my payment on time  before the 10th  why dell financial service imposed a late charge assessment fee after they received the payment on jan 9,2013 before the 10th  on dec 31,2013 i  emailed dell twice got not response i called their 1800-283-2210 it's tererible i was tranferred from one country to another  people who could not speak english well   recently i returned dell aspiron 660 the operating was window 8 when i was watching moviem online it froze all the time. i 'm  cancelling my dell preferred accoun right now.