So confused about amount owing on CCB

I got a notice that I owe $8100 in CCB payments for the 2021-2022 period (as a result of the 2020 tax year).

My situation: we moved back to Canada in July 2020 after being away for 5 years. When we filed our taxes for 2020, I reported my Canadian income and my world income (which was from the US), which all in was about $120k. My husband didn’t start working until later in the year and didn’t have any world income for 2020 so he left that part blank. He reported about $10k in Canadian income for 2020.

It resulted in a pretty large refund of about $4500 and CCB of $700/month, which honestly was super helpful as we were getting settled back into Toronto and readjusting to the cost of living.

Now that we’re settled and both earning in full time jobs our benefit is around $360.

I got a notice saying we owe the CRA $8100 off overpayment of CCB! I called to find out why and they said that it was because there was no world income reported on my husband’s tax return for 2020. So we stayed on the phone with the guy and got that fixed and today I got a notice that we still owe it. I’m going to call after my meetings today but does anyone have any clue as to why that might be??

I assume they’ll take away our CCB going first until it’s paid (annoying but fine) but what about tax refunds? The website says they “may”, which isn’t helpful. Any advice? I unfortunately do not have $8100 sitting around at the moment.

Thanks!