I owe Carrefour Banque some money after my banque rejected 2 regular repayments. Since then I am getting increasingly threatening text messages and phone calls daily from Carrefour. I have explained to them that I am a pensioner and will pay them in full on October 7th when I receive my next pension payment. Does anyone know if I can stop this harassment
Unless you have an agreed overdraft it is normal for your bank to behave like this - France doesn’t really approve of debt, unlike the UK. You need to tell them what you are going to do to put things right, preferably in writing, then it should be ok. You don’t want to end up interdit bancaire, so talk to them again.
I’m puzzled - “rejected 2 regular payments”.
Was that correctly, because you didn’t have the funds or erroneously?
If the former then I’d agree with Vero - you need to review things and speak with the banks, not having funds to cover regular, predictable, payments suggests you might be in a spot of bother and that will best be dealt with sooner than later.
If the latter, then surely you have the funds to give to Carrefour?
I’m sorry for your situation Gordon. One always need to bear in mind that bouncing a cheque here is a criminal, not a civil matter. That’s why cheques have endured in France long after they were discredited in other countries. My advice is to either arrange an OD with your Bank and pay Carrefour ASAP or keep communicating with Carrefour until the 7th. Then I’d dump the Carrefour card 
We only use it to access the checkouts.
I am sorry to see so many supermarkets advertising - buy your shopping now and pay in instalments… 
In my view, that can seriously tempt folk to buy more than they can really afford and/or need. The day of reckoning has to come some time… and that is when things can turn nasty for so many …
The best thing to do is to pay in cash and do not get tripped up by their offer. To take out a creditcard is just a temptation to let your budget go out of balance.
Best thing to do (1) pay off balance and (2) close account and cut up the card!