Settled Account / contact number *** not responsive

Good day , I settled the account that you guys have for Wonga , i sent proof of payment to ********** with no response to acknowledge my message. can you please send me my paid up letter as i need this letter to continue with my business, how do you as a company have an engaged line which no alternative. you seem very ***** and im glad Wonga said i should contact you should you guys not help then it will be their problem to fix this . I need someone to please fix this problem or take ownership of this problem