No matter what I do, I can't get my refund

I asked Samsung Estore to include my VAT number in my invoice. After 7 days, multiple calls, they failed to do so, so I bought my phone from another store. I immediately requested Samsung Estore to collect my phone and process a full refund. I have been calling and emailing weekly (sometimes biweekly), and till today, 2 months later, no one has come to collect my phone nor have I received my refund. I asked to speak to a manager on the phone, and apparently they can only escalate on email (which has probably been done already 10+ times). I have a brand new, unopened unit. It's been 2 months. I just want my refund please!