Returning illegal serves

The players I usually play with ABSOLUTELY INSIST on serving the ball straight out of their hand. No toss as the rules clearly mandate.

This type of serve is not legal for a very good reason; it gives the server a significant advantage, especially if the server is otherwise a reasonably good player.

Since I must live with this situation because these are my friends and do not want to cause a rift between us, I am trying to learn how to handle their illegal serves. Do you have any advice on how to successfully counter these eratic serves which seem to literally "explode" out of their palm giving me VERY little time to react? 

My skill level is probably intermediate and good enough to probably win the majority of my matches IF  my friends would just serve legally. I know this is probably an impossible question to answer, but my frustration level has reached the point where I am seeking advice from everyone. ANY help would be appreciated.

Thanks!

Jack

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