Meesho app - Size recived different and material of product is also not so good

I have ordered one shirt I didn't checked the size after receiving the order, I ordered medium size shirt but received small size. And as it was ordered as a gift so I directly give it to him and didn't checked it properly just checked meterial as I was really busy with my work, but it is too small for my friend and he returned it so I want to exchange it or else just want refund for that, And even the given quality is not satisfied. So as I know exchange period is over but I wanted to exchange as it was not fitted for him. I know it's my mistake that I didn't make request in given period but due to some issue I couldn't do it, and they made mistake I have ordered "M" size and recived "S" size so I requested then to exchange it they are saying it is impossible . Even filed a complaint again and again they are just saying it is impossible.
If I can't even exchange and get refund back its my loss because my money is also gone and even that shirt. I even mentioned that shirt is packed as it is and not even used so please give me solution on this.