In possession of original slip but kicked out

On the 27/7/14 (Transaction no. CA***) I bought an Asus Laptop at Hi-Corp in Carnival Mall with 3 years extended warranty. Then I had to return it back on the 22/8/14 (Transaction no. CA***)as it have few USB ports & I was given a HP laptop. Then 27 July & 22 August invoices are both written 3 years warranty. Then in March 2016, the laptop gave me problems i.e. Windows not activated, slow & camera not working.<br> <br> On the 20/3/16 , I went to Carnival with my laptop & my original 3 year extended warranty slip to book it due to the problems mentioned. I met 2 ladies who kicked me out that I don't have an extended warranty on this laptop. Then I told them I have this slip which was issued to me on the 22/8/14 with an extended warranty. They just told me that they don't care that's what they have on the system. Then I sent my laptop for Windows activation privately & the professional said he may not be able to fix the camera(windows activation currently in-progress). This situation is very stressful as I wasn't helped by Hi-Corp where I bought laptop & the receipt I was issued is written that I have 3 years extended warranty. How can I helped in this regard? <br>