Frontech — complaint for harassment

Even after calling you and complaining about the same issue still the company nameed frontech is now sending me e-mail from email id [protected]@gmail.com stating the non payment of fees. Which i already cleared and earlier was getting calls from [protected], [protected] and [protected].
Now as i am not answering calls they are sending emails.
Please look into this as soon as possible and give a resolution as its a mental torture from a month.