Samsung Summer promotion buy back vouchers

I received a summer promotion buy back voucher for R4500 at Takealot. I purchased for R1500 from them using the voucher code received from Samsung. When I wanted to buy again I was told by Takealot that this was a coupon and not a voucher. The terms and conditions stated Voucher. I had to use the full value at once or forfeit the rest of the voucher which is R3000 I will be forfeiting. It does not state this in the terms and conditions of the promotion. I am struggling to get hold of anyone at Samsung to assist me with this. Takealot gave prompt feedback but said I have to take it up with Samsung who issued the voucher. If this was a condition it should have been stipulated clearly as such in the terms and conditions or a lot of people are going to forfeit a lot of their voucher value. Takealot says I should request Samsung to issue me with another voucher for the remainder of the balance. Hoping Samsung will be able to assist me to resolve. I hope Takelot is wrong but I am unable to get hold of anyone from her Samsung promotion team and urgently need to know whether I should perhaps cancel my previous order which have not been shipped yet to try and get my voucher re instated and use all at once if that is indeed a requirement