Huge trash (most recycle) pick up bill for retail tenants

[June Kim]

Hello I am trying to find a way to reduce a huge trash bill (mostly recycle) for a ground floor retail condo units I own. 70% of the bill is due to recycles.  There are 5 retailers (4 food and 1 clothing). The problem is the 2 tenants who have many cardboard boxes. Right now, we have 5 of 2yr recycle dumpsters in the trash room (2 additional ones for regular trash). These are picked up 6 times a week.  I see that if each tenant flattens their boxes all the time, it will reduce the cost but this is not done consistently. What are the ways I can reduce the volumes? 

Additional Questions I have in my mind are: 1)This property located some distance from me and so I am not entirely sure if 5 of 2 yr dumpster pick up X 6 times a week that my private trash service company is telling me I need are indeed accurate. 

2)This is a condo unit, however the Condo is refusing to take care of the retail condos' trash pick ups as the residential side is being taken care of for free by the city. The city says they do take business' recycles for free but since ours are rather big in volume, this appears to be rather tricky to make arrangements (city says they only pick up once a week). Anyone who has retail condo units dealt with trash issues? 

Thank you in advance for your advice!