If You are using e-mail client (e.g. Outlook), the junk e-mail might have been blocked by Your e-mail domain. Check e-mail "manually" (e.g. for gmail, check it via google website instead of via Outlook). I had this issue once applying for Aer Lingus programme. If it is not the case, then I suggest to contact Wizz - the reply message is containing Your application ID, which may be useful in further process.