Harrasment calls

I'm writing this review with a heavy heart. I have an account with finchoice and it's in arrears which I have made arrangements of paying it and which I'm every month.They have handed my account over to the collections department Im being harassed everyday every hour Monday to Monday and it's not like I'm running away I'm paying the arrangement as agreed this other lady said they going to call me until I finish paying them...I have acknowledge my account and I'm paying but it has gotten to a point whereby I want to change my phone number because it's as if I'm the only one that owes them money because I get called the whole day that I need to make an arrangement..I don't know anymore is there a place I can report them for harrasment?