Our implementation language is PHP (using the CodeIgniter library).
My requirements are this:
Are there any SaaS services that can remove the hassle from all this logic for me? Even better - provide a secured, hosted form page on which the user can provide their CC details (removing the need for me to have anything to do with credit card info)?
Competitive pricing model definitely a plus.
As profitphp pointed out. That's not quite how it would work. The auth typically drops off within 2 or three days if it has not been settled.
So instead you would capture the card details upfront, by redirecting the user to a page hosted by your Payment Service Provider (or PSP which is the lingo for SaaS when it comes to payments). When capturing the details you want your PSP to perform a zero value authorisation, which will just confirm the card details are valid, and then return to you a token id.
24 hours before the event you then run through the list of all tokens that haven't been cancelled and submit them to the PSP again, but this time performing a full auth/settlement. There is a reasonable chance though that some of these will fail to auth (lack of funds or expired/canceled cards being most likely), so you need some business logic to handle that.
Alternatively you could perform auth/settlement a week before the event, which would allow time to recontact the customers where auth has failed. You would still be able to offer refunds by submitting the token id to the PSP.
Mostly any Payment Service Provider will offer this functionality.