Staff Response I bought too many inventory expansion thingies

I purchased 3 16 slot inventory expansion tickets, and when I try to use my last one it says "cannot expand inventory any more."

I just assumed if I didn't have 16 slots remaining before 192, it would just fill in whatever it could. I'd be ok if it only gave me 15 or 14 more slots.. but I can't use it at all and it's a complete waste. Is there something someone on their side could do? Are refunds possible? otherwise I have to drag a 15$ item out of my inventory and throw it on the floor because I cannot use it.