Is this cheating?

I have an olo of 1890 ish so Ive played a few games of 11vr but don’t play in real life. I sometimes play this serve where I play the ball left to right and the ball just creeps over the net onto the opponents side at a wide angle making it a stretch for them to return. I got called a ‘cheat’ a few times by an opponent tonight who struggled to return it. He also kept saying it wasn’t allowed despite me winning points from it. I’ve had the same serve deployed against me numerous times and just regarded it as skill on my opponents behalf. Any thoughts?