Pugilist Haymaker Feat

Greetings all. 

My GM and I have a question concerning the Haymaker feat for the Pugilist class. At level 5 the pugilist class gains the following.

Level 5: Extra Attack

You can attack twice instead of once whenever you take the Attack action on your turn.

Level 5: Haymaker

When you make an attack with an Unarmed Strike or Pugilist weapon, you can expend 1 Moxie Point to swing with wild abandon. On a hit, regain the expended Moxie Point and you deal maximum damage with that attack.

And previously at level 2 gains moxie points.

Level 2: Moxie

Your experiences of beating the odds have given you a moxie you can channel in the midst of battle. This swagger is represented by a number of Moxie Points. Your Pugilist level determines the maximum number of points you have, as shown in the Moxie Points column of the Pugilist Features table.

You can spend these points to enhance or fuel certain Pugilist features. You start knowing three such features: Brace Up, One-Two Punch, and Stick and Move, each of which is detailed below.

When you expend a Moxie Point, it is unavailable until you finish a Short or Long Rest, at the end of which you regain all your expended points.

Brace Up. You can use a Bonus Action and expend 1 Moxie Point to brace for attacks. When you do so, roll your Fisticuffs die, and gain a number of Temporary Hit Points equal to the number rolled plus your Pugilist level and your Constitution modifier. These Temporary Hit Points vanish if any remain after 10 minutes.

One-Two Punch. You can expend 1 Moxie Point to make two Unarmed Strikes as a Bonus Action.

Stick and Move. You can use a Bonus Action and expend 1 Moxie Point to make an Unarmed Strike and take the Dash or Disengage action.

With the above given, can the Haymaker be used multiple times in a single turn? 

On my turn I used my attack action to make 2 attacks. Used a moxie point to make a Haymaker attack which hit for 15 points of damage, with the successful attack regained the moxie point. Spent a moxie point to do a One- Two Punch as a bonus action giving me 2 more unarmed attacks which I used a moxie point on each to again make a Haymaker attack which both hit and therefore no moxie points were lost. Both attacks again doing 15 ponts of damage for a total of 45 points in my first attack. On my second attack again using a moxie point to make a Haymaker which hit and another 15 points of damage for a total of 60 points for the turn. 

Is the multiple use of Haymaker allowed by rule or is it a once per turn feat?

Let us know what you guys think. 

As long as you have the moxie points, it can be used whenever you make an unarmed strike or use a pugilist weapon.  I don't see any limit per turn (besides the limit on number of attacks you have).

I agree with that statement. The rule states you can use it "When you make an attack" and does not include any "once per turn" restriction. As long as you have the Moxie points you can use it on every attack that hits.

I agree. This feature is usable as long as you have the Moxie points remaining, so even if you start the fight with only 1 Moxie point, you could use it on every attack until you miss.