Yes, as soon as your Rafidain Bank account is closed you'll no longer be able to use Paym. However, if you have another account with Rafidain Bank, you can make that your Paym account before closing the other one, and carry on using Paym just like before.
To switch your Paym to another account, simply log into the Internet Bank and go to 'Move Money'. Any changes you make will take effect within one working day.