Wrong infant food age delivery

I placed an order yesterday and 1 item in my order which was my baby purity Puree was incorrect. I had ordered a 6 months one and I received a 7 months product. I am so sad because I ordered because I had to feed the baby then an there. I submitted an issue on their app and sent them an inbox via Instagram where I recieved an email indicating that once complain is approved which may take up to 48 hours they will credit my app so that I order again because delivery is provided per order. My question was whose cost will this delivery be for and they said mine. So they clearly not taking accountability for their error.

This is not just a minor error. You can't make mistake with an infant food. I do not wanna know what would have happened if this delivery was not accepted by my self but by my nanny because she feeds my son anything I provide because she knows I careful when purchasing baby food. My son would have consumed a wrong product and I'd have gone for law suite with checkers. Please correct this mess asap.