I'm not a contractor, but...
If you're willing to lose the customer, you can put a "Builder's Lien" against their property. If they ever try to sell that property, you will get paid out of the selling price before the property changes hands. This is something you can do yourself without hiring a lawyer. Phone your local city hall or land titles office to find out the procedure.
Alternatively, find out who actually owns the mall. You can do that at your property tax office cuz the property tax bill will be sent to the registered owner of the property, not the management company. If you can talk to the owner(s) of the mall (or the head of the company that owns that mall) and just let him know the situation, he might not be aware that his management company is not paying contractors on time and in full, and might give them directions to shape up.
No owner wants his agent to give him a bad reputation cuz he knows that if he changes management companies, his mall will still have a bad rep amongst local contractors, and then it'll be his problem, not the old management company's. (That's why you often see "UNDER NEW MANAGEMENT" signs on businesses. They want people to know that the management has changed so that if they were fed up with the old management, that's no longer a factor.)
Heck, even if you tell the owners that their management company is so poor in paying it's bills, you're thinking of just putting a Builder's Lien against their property, that would certainly get the owner's attention. That's cuz in that case, his representative is representing him in such a bad way, it's giving him a bad reputation. And, he knows that if you take out that Builder's Lien, he's gonna have to pay for your work eventually, no way around that. Since you can include interest at the prevailing rate on a builder's loan, he knows there's no point in waiting and letting inflation erode the amount he owes. It's better to pay now and keep his record clear.
But, I expect that your problem customers are having a hard time paying you, and that's the source of the problem. If they had the money, they'd pay on time and in full.