It definitely is abnormal, although reviewers usually spend quite little time in practice. I highly suspect this is a conference for MONEY. You'd better withdraw your paper.
There are several (at least some) serious conferences in almost every field. I do not mean the conferences are large or their papers have very high impact factors (but usually they do). I mean they all have high reputation. A direct way to find such conferences is to see who submit their papers to and who attend the conferences. My suggestion is only to submit to these conferences, for your own reputation.
It seems that the conference is 'related to EE but has wide research topics including signal processing'. I may assume your paper is about signal processing. For signal processing, there are a bunch of serious conferences including: ICASSP, GlobalSIP, Allerton, Asilomar, etc. You may also consider some communications conferences which also cover signal processing topics, such as ICC, GlobalCom, WCNC. If your research lies in the theoretic part, there are information theory conferences like ISIT, CISS, ITW.