The issue that you are experiencing is actually a desgin feature of the CCSFG where it is not capable of submitting a contact that already exists. We do offer a modified version by request that does not have this limitation, but it is only offered by request because there is a minor security concern.
I would suggest taking a moment to read more about the security risk of using the mofidied version here.
If you would like to have the modified version without the limitation on updating contacts please send an email to firstname.lastname@example.org and we will be able to assist you further!
Tier 2 Support