Stark collection - Exchange only one delivered one balance

I ordered * sleeveless tshirt from stark collection, received both wrong tshirt, asked for exchange, delivery boy came in the morning to collect it,gave both the tshirt to him,later another delivery boy came in the afternoon to collect,I told him that I already handed both the tshirt to the previous delivery boy,he said OK,
Later after some days I received one tshirt back,I asked about the other one, the delivery boy said that the other person will bring it,I said OK,
But till date I received nothing, n I had paid online, I complained to the help centre, but they r saying that I canceled the exchange
N why will I cancel,
OK if I canceled then why they did not refund the money ,n now when I again spoked to the help centre, they r saying that they cannot do anything
That means my tshirt n my money is gone,
I didn't expect such service from meesho
If your delivery person makes a mistake, why should the customer suffer for it