Couple of questions about CVV and AVS alerts

[Themirroredsoul]

I have a question about CVV and AVS alerts. I have risk manager rules set up for both. CVV is set up as a block if invalid. AVS is set up as well. My question is will the payment be blocked if no CVV is put in as I'm showing CVV unavailable? Can they order without a CVV online? I see that there is a separate setting for CVV unavailable. I can set both up but am trying to make a decision now. I am getting an AVS mismatch that looks like a zip code issue. The zip code is in the city the customer put down. Also, the other info I checked matches the info I was given.  I just wonder about CVV because if they don't have to put it in then that could inform my decision. If I have CVV issues blocked to decline will it decline if they do not enter?

Also, can the longer postal code cause a mismatch? If they use the 5 digit and four digit code, can it mismatch? Is the code in the risk alert by billing the zip code the bank has?

Thanks for any help.

Btw, I already reached out to the customer to contact me. I have looked at the Risk Management help articles.