Sorry to hear you’re dealing with this. I had a similar runaround with Otterbox last year. I rarely do this, but I ended up having to threaten a charge back on my credit card to get my issue resolved. Once I did that I actually got a call from a CS rep who handled the situation in a few minutes. This was after weeks of screwing around on email and chat. It was way too big of a hassle for a stupid phone case.
In fairness, I’ve had other bad CS experiences when dealing direct with case makers, which is why now, if at all possible, I just wait until the case is available on Amazon with Prime shipping.