First, while credit card companies and banks can chose to honor disputes of any age, your rights under the FCBA protect you for only 60 days -- and the FCBA doesn't apply to debit cards at all.
My tip -- that you should never use a debit card and with credit cards you should dispute charges before paying the bill -- is correct in spirit but not in the letter of the way I worded it, so mea culpa on technicalities but the point is correct. The FCBA only grants you 60 days to dispute a transaction (after the statement cut, not the transaction itself).
Also, CC disputes have some consequences. Companies aggregate & share lists of customers that have charge-backed. Finding yourself on the list can see you turned-away from legitimate, good businesses that have to protect themselves against dispute-prone customers.
I see 6 month chargebacks on a regular basis (dealing with consumer fraud is fun), so these definitely happen, they're possible and if consumers can do it when they are the ones defrauding the merchants there will be a lot less trouble when it is the merchant doing the defrauding.
In many cases the cc company debiting your checking account is automated and there is no step for you to verify other than to periodically go through your statements to see if you have taken on any ghost charges.
What the parent meant was "after you paid the bill". It's hard to go back later and say the charge was fraudulent after you received the bill and opted to pay it. In theory, payment = acceptance of charges.
Theory doesn't matter much here. Especially not with automated debiting of checking accounts to pay the balance or some amount of interest or a combination of those.
As a customer of the card company you have the right to dispute charges as far back as you want, whether they'll honor that or not is a different question but typically up to 6 months in a card-not-present situation should give you no problem at all. And once the complaints about this company start rolling in it will get even easier.
Mass chargebacks are a very powerful weapon in the hands of organized consumers.