Missing balance on gift card!!!???!!

[LittleLidia07]

Spoiler

I am so frustrated and disappointed with Sephora. Last year in April I had returned items for a total of $135.68 to a store location. The cashier let me know she would put the balance back onto a store gift card. 

I still have the old receipt and it shows one balance for $73.50 on a gift card and then $62.18 on a merchant credit card. 

Yesterday I went in and bought lash glue for $19. And the cashier let's me know there is a remaining $19.95 on my gift card!!! This card has never been used since the time of issuing. 

I called customer service for Sephora.
They have no information on their side of this since it is a store transaction. 

What the flippin heck is going on !!!! How is my balance missing and why am I only getting a portion of my return on a card!!! My fault completely for having any trust in your employee's but still!!!!!!

Has anyone else experienced similar and any advice would be greatly appreciated! 

Spoiler

[keelybt]

@LittleLidia07 I will send you a PM for more information.