Useless gift card

My aunt gave me gift card I wanted to buy cellphones in the shop they told me I can't buy it because it's a gift card why do Truworths limit on what you want to buy I feel that the Truworths it's fair you can't make the customer buy clothes while I don't need them why is your gift card limit the services and please before you sell the gift card make sure your customers that they need to buy selected things the shop and please print it in black and white in your slips so that customers must be aware lastly I don't know what to do with the stupid gift card can you please let me know what to do with it because I can't loss R2000 in it