Service continued to deteriorate

I bought a fridge from Rentoza on the 25th November 2022, Payment was done same day and the fridge was only delivered in January then my January instalment went through successfully and just lastweek the 25th of February my monthly instalment went off successfully and my bank statements and Rentoza app has proof of my payments. Yesterday I received a letter of demand from a third party call ACCOUNTABILITY siting that I’ve defaulted my February and demanded payment be done within 20 days or this may result in a negative listing. I sent them emails and proof of my payments attached yet they are still harrassing me. The contact number they shared on the letter of demand *** does not exist.