on every 15 secconds, I'm getting big spam inside of my console with these messages 

(19:50:44) | [Economics] Saving balances for players...

(19:50:55) | Saved 62,343 ents, cache(0.02), write(0.01), disk(0.00).

And I don't know how to  stop this because it takes a lot of my server ram from it 

This plugin saves when your server saves. Are you saving the server every 15 seconds?

No i've set met save time on every 10 minutes so I don't know what is going on here but when i got the time today I'll check it again 

Something is triggering your server to save every 15 seconds, as you see Rust’s save info there as well.