Will Grigg's brace plus goals from Febian Brandy and Jamie Paterson handed the Saddlers an npower League One double over the below-par Dons, for whom Ryan Lowe and Dean Bowditch were both on target.
Robinson said: "It was shambolic defending from us - the defending in that first half was as bad as I've seen in two years of being here.
"We backed off, let them turn and shoot in our box and walk past us - it was kamakaze stuff really. I don't accept it and I won't accept it either. That back four won't play together on Saturday anyway.
"There were players out there who didn't deserve to wear our shirt - it's as simple as that - and they won't if they continue like that. I feel I've got to do my job over the next few weeks and there's certain players who have got to stand up and be counted.
"If they can't stand up and be counted against Coventry then I'll make changes in January.
"There will be a slight bit of money available, but I'll have to make my own money and maybe one or two people will have to leave the club to make way to bring players in."
Lowe put the Dons ahead after only six minutes when he stole in unmarked to head home Adam Chicksen's cross for his fourth goal in as many games.
But Walsall scored two goals in 10 minutes to turn the match on its head, first when Brandy bundled his way through to lash the ball into the top corner and then when Grigg skinned Mathias Doumbe to curl the ball past David Martin.
Dons forward Bowditch made it 2-2 when he neatly slotted in Lowe's lay-off, but Grigg restored Walsall's lead two minutes before the break, tapping in Craig Westcarr's low cross from close range and Paterson made it 4-2 at the death when his curling shot was deflected past Martin.
