Meesho — Product missing for online order

I purchased 2 sets of kids tshirts (each set with 3 tshirts) on 3rd May and made online payment. I received a notification from meesho that it will be delivered on 8th May in single package however when I received the product on 8th the package has only one set and the other set was missing.
I raised complaint with customer care and was assured that the refund will be provided for missing item however on 9th May I received the email from meesho mentioning that refund request has been rejected and no refund will be made.
I feel cheated and it is not fair in first place to combine the orders if they can not maintain integrity and provide support for their mistakes.

Need some help to fix it.