At least het the functions working!!! I want my money back

First an old gripe. I had this up few years ago. It disappeared off my iPhone at the time I presume HP claimed their intellectual property and apple pulled it even though I paid for it!! That is atrocious. I paid for it do not touch it.

I obviously wanted it more as I shelled out again $15 this time to HP to have the product. Now however Im furious. How do I get refund for this faulty app? The calculator looks like the beloved 12c but the functions do not work!!! It gives error if you try to calculate interest of a stream of cash flows!! What the heck, the looks is not why I buy this. Get the formulas to work before you sell this!!! I want my money back!!!!

Eternalspring22 about HP 12C Financial Calculator