Being Abused by institution

Im writing this report not really happy as how my account is being delt with, My account is currently in arrears which I acknowledge that and really not happy about that,i have received several calls from the institution in regards with arrangement with I have made an arrangement with them starting from the 20 April 2015 since yesterday I have been receiving calls from the legal department now threatening me and telling me that they are coming to my work address to garnish my salary and I did advise them that already I have made an arrangement to pay account why must I now be treated as a ******** while I'm willing to pay the account... why was there any need for me to make arrangement when really u want to harass me... I'm writing this letter not in a good space and on tears that I was harassed by you, when I was paying ok no one complained now that I need help you guy have the right to abuse me.