Damaged item bought, with no feedback

I bought a 2 piece set for my son on the 3rd washed it on the 9th and the stitching right down the one side was out. I contacted their complaints, told me they will make contact within 72 hours it's been 4 days since. No contact. I don't have the slip anymore and literally just wanna exchange the item...they investigating yet the default item still in my possession. 4 days and no one even reached out even after I gave my cell phone number as well.