Return and refund order purchased

Helo,I made an order from Temu on the 29August of which it was collected by GFS express courier company,so now I want to return the order back to Temu,and it is impossible to do so because the order is still with GFS express,when I call they say the order cannot be found but when I track my order it says it is in transit under GFS express.i have been trying to reach out to them but to no avail.please help