HMRC and receiving letters every bloody week/AIBU?

[avamiah]

About 4 months ago I called HMRC and informed them that my circumstances had changed and that i wanted to stop my claim for child tax credits.
However about a week later i received a letter stating that i have to make a repayment as i had already been paid money in the tax year.
Fine,
No Problem.
I set up a DDebit and have been paying it.
However, since i told them i don't want any Child tax credits, i have had letters every week off them, telling me how much i owe and when it has to be paid etc.
Its ridiculous.
What is their problem?

Did you call them up and arrange the direct debit over the phone or did you set it up online yourself? Either way give them a call, sometimes it can take nearly 2 weeks for letters to be received after they're sent by HMRC so it could also just be a crossover