Not providing replacement of the wrong product given by them

I have ordered a tinted sunscreen from the brand and paid for the new formula, which was updated by the brand itself with new UV filters, but I have received the old formula and the older packaging. After talking with them. They agreed for replacement, but from past approx one month, they are not providing with the replacement or any kind of refund. Kindly look into the matter and help me regarding the same. I have contacting them from past one month, but they are just telling me to wait and not providing with any resolution.