Harassment

I had a loan with wonga and they handed my account to a collections company which I made arrangements with them and settled the account. A day later after the account was settled I started receiving calls from HTN attorneys about the same account I have settled, I then forwarded proof of payment and explained to them that I had already settled with the previous company and that I was surprised by their emails demanding payment. Even so they never stopped with demanding payment, they requested proof of payment again and I sent it. This happened about three times. I then contacted wonga and they acknowledged the payment received and said would update my account on their side. Yet HTN attorneys are a NIGHTMARE!!!!!! They won't stop calling me and I have no business with them.