Poor to customer service

It's been about four years now and after notifying these consultants and constant private and threaten messages and phones from them..... I have in previous conversations with there consultants explained to them.of my current financial status but these people just don't adhere or listen to your reasoning or statements. Reference number ********** ********** 14 which in my records they have had for.more than 4 years now they now demand repayment on ......... There customer service is really appalling as they call you at 5am in the morning and at some times at 9pm at night........