Sirvape refuses return of clearly faulty devide

I ordered a particular vape starter kit from Sirvape. During the first two days of owning the device, the 5-click on and off mechanism worked fine. From day 3 onwards, however, the device would respond to the 5-click mechanism only intermittently and it took many attempts before the device would respond to the clicks in order to either switch on or off. This is clearly a fault in the device as I have been through a number of devices and never has it been required that I make a number of attempts at the 5-click on/off action before the device would respond to it. I contacted Sirvape reporting the problem and they arranged for the device to be collected from me and sent back to them. They contacted me saying that the device was working correctly and sent me a short video demonstrating the successful switching on and off via the 5-click mechanism. Note however that in the video the device was switched on once, switched off once, then the batteries were taken out and inserted again upon which the device switches back on automatically. They thus refused to the return of the device and sent it back to me at my own cost of R80 for the courier. I received the device this morning. Same problem. And this time I made a video that shows how it took two attempts to get the device switched on, and that only on the SEVENTH attempt did the device switch off again. What is more disturbing is that I noticed clearly that in fact my device box was never opened. This is clear to me due to the taping I used in order to secure the lid of the box to the box prior to sending it back to Sirvape. The clear tape (sellotape) that I put onto the box was asymmetrical, uneven, and thinned toward its sides due to how a broad width roll of sellotape tends to tear down the middle when you try to pull off a piece for use. This exact taping was fully in place and unopened when I received the device back this morning. Did they thus use another similar mod for their video? I cannot state this as a fact but I do strongly suspect it. I will now be contacting them again, sending my video and once again request a return for a refund. I will update on the outcome here. Hopefully this time they will take the route of integrity and ethical business practice.