Refunds - Waiting for refund for the Laptop returned from last SIX MONTHS

I have purchased Dell 7378 13' Laptop (Refurbished) in December' 2016. Upon receiving the machine, I have initiated return and received authorization label and returned to Dell warehouse. Dell warehouse confirmed that Laptop was received by them on 7th Jan'2017 and informed me that refund will be credited in 30 to 45 days. This happened in January 2017 and this is June'2017. It's been already 6 months and I have not received my money back. 

I have contacted customer support team multiple times (nearly 15 to 20 times) and every time they have told me that something is pending(they are never clear on what is pending)  from verification team, after each time, I have called order verification team to see if anything is pending on my order/account, but they have told that account is clear and there is no activity pending. And when I contact customer support team again upon order verification team confirmation, same story repeated. I have asked both the teams for escalation contacts and asked them for way to work together to resolve this, But I did not get any response or solution for this.

I really want to escalate this to higher level, My funds are being held by Dell even after returning laptop 6 months ago and without anything pending from me/customer. and I have spent lots of time on reaching customer support and order verification team without any result. This is really frustrating experience with Dell teams 

I hope I will get some solution from this and really appreciate your help in anyway to resolve or escalate this. I am really tired for reaching both the teams and hearing the same version from last 6 months.

Thanks,

Kishore