dawnh1963 Thank you for contacting the giffgaff Community.
Firstly try to not use your remaining credit any further from now on, especially for DATA this will use it up in no time at 5p per MB!
To contact a giffgaff agent you will need to fill in the agent form here https://support2.giffgaff.com/app/ask/Top-up-balances-and-goodybags/goodybag-allowances-or-credit-balance-incorrect/form/
giffgaff agents reply within 4 hours in most cases however, can take up to 24 hours during busy periods (agents work 7 days a week from 8am to 11pm).
You will see when an agent has replied in the "Messages: From Agents" box which can be found half way down the right hand side of your "My giffgaff" page or you can access it direct here https://giffgaff.com/support/questions