No Feedback or correspondence

I've been under debt councelling via debtbusters since 2016 and generally things have been great and they have been very helpful. I finally reached the point where I could settle all accounts and are now awaiting my clearance certificate. I have settled my accounts on 26 April 2024 after receiveing my settlement values. Its now been 2 months since settlement and Im still awaiting one paid up letter of which I was advised there is an outstanding balance on (This account and balance did not reflect on the settlement values given). I've disputed this outstanding balance because according to my records that account has been paid up on Sept 2022 already. Ive asked debtbusters to investigate and advise a solution and reason for them stopping to pay and removing the account while I still paid my full rehabilitation installment to debtbusters. Since the dispute 3rd of June I've had no response from debtbusters whatsoever. I've phoned and requested Spokazi,who is handling this matter, to contact me, but got no call back. I have sent 9 emails since 3 Jun to follow up on the matter but they seem to be ignoring all my emails. I'm urgently awaiting that clearance certificate and would like to know the way forward and get some advice, but I'M GETTING ABSOLUTELY NO RESPONSE FROM DEBTBUSTERS. Please help or advise if I should take this matter to higher authorities. Thanks Marius