Incredible Connection unfair business practice

I purchased a laptop and extended warranty. During warranty period the laptop gave me trouble and due to lack of parts Incredible Connection provided me with a gift voucher to the value of the item. Now they are only allowing me to use the gift voucher in store and not online, yet all the deals are online. For example, Samsung Galaxy S10e online is R8000 but in store it is R14000!!! Their in store prices are ridiculous, yesterday I went into store and they tell me they don't have any store specials only online. For me as a customer, this is a ******* system and they don't know what customer service is.