After members save 60 item on the database, I need monthly plan or subscription automatically canceled even if the month aren't ending

This is what you need to do.

When a member clicks on the button, add something to the database. You can do this with the wixData.save() api.

Then in the then after the save write this -

import wixData from 'wix-data';
import wixUsers from 'wix-users'
// ...

let toSave = {
  "title":        "Mr.",
  "first_name":   "John",
  "last_name":    "Doe"
};

wixData.save("myCollection", toSave)
	.then( (results) => {
		let items = results.items; //see item below
		let count = items.length
		if (count >= 60) {
		
		}
	} )

Then inside that .then((results)) you need to get the users plans and cancel the first plan they have. https://www.wix.com/velo/reference/wix-paid-plans/cancelorder