Refer to manual that came with unit.
Big hint page 14
Even bigger hint and book mark this site.
https://products.geappliances.com/MarketingObjectRetrieval/Dispatcher?RequestType=PDF&Name=49-50283-11.pdf
Mark and unhook all the tubes from the filter. Take it out and place it on a table horizontally. This is all about correct leverage.
While holding the reverse osmosis system in one hand, slide the wrench into a canister and turn it counter-clockwise.
If this still does not work, you may have to soak the filter canisters (bottom housing part ONLY) in warm water with vinegar and try the steps above again.
How to change 10 RO Pre Filters
There might be a low pressure sensor inside the purologix system that is preventing the cooler from dispensing water. In that case you may need to install a booster pump to increase water pressure into the storage tank of the ro system.
Check if you installed the ice maker correctly as well.
https://www.wecofilters.com/pub/media/productattach//i/c/ice_maker_kit_manual.pdf
The tank should have only 5-10 psi when empty of water. If your unit sat for any amount of time your reverse osmosis membrane may have a problem. was all the cartridges changed? Should be yearly.