... 2 days ago I sent them 150 dollars - I received 3 keys for 45$, and one key was invalid, 100 dollars were stolen from me, ...
in this case probably you received
2 private keys and
1 voucher code and you received a voucher code because the site most likely run out of that specific chip size
if your invalid key starts with other than K and L, it's definitely a voucher code
so, please do a quick check on it but
don't post the code here
This voucher is invalid or already redeemed. - I tried earlier, the key begins with the letter K and it does not work as a voucher. also it is not activated in electrum. I wrote to the mail indicated on the site, I am waiting for the third day, there is no answer