Debt payments not distributed accordingly

I have been under debt review with Debt Busters since 2016 and according the communication from Debt busters my payments will end in 5 years, however this year they advised me that I still need to pay for another year, which after a while I still went along as I wanted my debt to be cleared and I have paid for 5 years and didn't want to waste time and money spent. I have religiously made payments every month on the same date, yet for the past 2 months Debt Busters has failed to distribute payments on my accounts and yet they still send me the payment profile showing that they have made payments, however the creditors are harassing me on a daily basis for payments and when I try contacting them via email I get no response from them.