UltraCrypter payment system is not recognizing ransom payments and victim’s are unable to download the decryptor. Since the first two versions had flaws in their encryption algorithm that allowed Kaspersky to release free decryptors for victims. With that said, the payment system seems to be broken. As victim’s make a payment, the system does not recognize that a payment has been made, the timer runs down and the ransom amount doubles. If you have no choice and were planning on making a ransom payment, it is strongly advised not to pay the ransom until these issues are resolved.
Source: https://www.bleepingcomputer.com/news/security/ultracrypter-not-providing-decryption-keys-after-payment-launches-help-desk/