Appalling Service and Communication

I made a payment arrangement on the 21st May 2025 to pay my first amount by the 16th of each month when I get paid ***. I received an email back and it was stated that the payment arrangement was accepted. On the 14th of June I paid my first amount of R3000 as I said I would, sent through my POP and it was captured. 2 days later and ever since I have been hounded by calls that my account has been turned over to Nimble and I'm getting calls from so many different debt collectors. This needs to be rectified ASAP or I will take this the legal route.