Electricity billing, from imoact metering

I have app**** for pre paid meter and made arrangements of paying because impact took over on another company for services and I had to pay the whole am as if I have just moved in the complex that was in March 2021 I was told now the account is fine On December they send me a letter saying am owing them R1300. They made a mistake in March with their accounts.

Which I tried to argue with them about it one thing about Impact meters you can try and argue you never win because they don't want to accept their mistakes

Today I get and email saying I have defaulted on the arrangements so they are canceling the arrangements and the want the whole amount

I called them but it did work because they are ever correct

Am just so dissapointed about their communication and unfriendlyness