If you are below what the Colony Hub says is protected that that is a problem. If you’re above that though, then that is the occupier taking resources from your base above what you produce. If you examine what you produce add that to what they are taking, it should be no greater then your overage from the Colony Hub’s safe amount or some lesser amount (if their fleet isn’t big enough).
For instance if you are producing say 6k/hr and you have a level 20 hub (protects 10k of all but your faction rare), it would suggest you have at least 18,253 ore and they are only able to take the 8253 part. If you have far more then that, then it just says their fleet is set to take 8253 ore/hr which could be either because that is the max it can take or because they set it to that for what ever reason (could be a several reasons).
Note that you can stop them for awhile (arbitrary and based on when they notice your colo isn’t giving ore anymore) by making the ore above your safe limit disappear somehow. Either by using it or listing it on the trade platform. Be aware listing comes at a cost, first in credits for what ever amount you list, then 1% of the listed amount of resources is taken if you cancel it (does it for expired listings too I think).