What is impossible?
You haven't clarified precisely what.
What credit has been disappearing?
Cash credit?
Allowance balances?
Which ones?
If cash credit is disappearing then you must be buying something with it or using services that get charged to your cash credit balance.
http://www.48months.ie/membership-plans/other-call-charges
http://www.48months.ie/membership-plans/international-calls
If your allowance balance(s?) is (are?) being depleted then you must be using the relevant services.
If you think that your data is being used faster than it should be then you should use you phone's data usage monitor or an app to track what's using it and when.
If you are still confused then you should contact 48 support for clarification:
http://www.48months.ie/help#ask-a-48-agent
Note that a Netflix movie could feasibly use up several GB per hour depending on the quality and other factors:
https://help.netflix.com/en/node/87
Hope this helps.
