You mean you cash credit?
Bear in mind that some services are charged from you cash credit balance.
E.g. international calls/texts, calls to "special" numbers (e.g. 1850/1890), MMS/picture messages etc.
See here for some services that are charged from your cash credit balance.
https://www.48months.ie/membership-plans/other-call-chargeshttps://www.48months.ie/membership-plans/international-callsIf that doesn't explain it then contact 48 support and they should be able to help.
See the link in my signature below.
Hope this helps.