Borderline harassment

For the past 2 months, after I diligently made an arrangement for payment and paid as per the arrangement, I continuously recieve phone calls (sometimes 4 times a week), numerous sms' and emails regarding the outstanding amount. I have one payment left for next month. This is borderline harassment and unprofessional from this company. Now they have sent me an sms stating that the account is 30 days overdue and will soon hand me over. What is the purpose of making an arrangement????? This is the most awful service and I have notified the partner hospital of Lancets awful services and harassment. And I can see on hello peter that I am not only client who has this problem. So why have they not sorted it out??!! It is *********. The credit law states that only 30 days after an account (this is if no arrangement has ever been made) has not been settled may they take some sort of action (as in notify the account holder). Not this continues harassment!