If this is critical feature for you then you can request a refund using the link below.
There are various apps out there that claim to replace the functionality and provide valuations (e.g. Deductible Duck) or you can get valuations at Salvation Army etc, however there is no ability as yet to import donations from these apps into Turbotax. In the help page on Turbotax there is a comment but not seen any other info about this - "COMING SOON: We’re working on a new tool to help you look up the fair market value of your item. We expect it to be ready soon, but you can file without it."
According to a conversation with customer care, 100k people were using the service out of 40mil returns so they decided it wasn't worthwhile to maintain.
Refund:
https://ttlc.intuit.com/turbotax-support/en-us/help-article/intuit-refunds/request-refund-turbotax-p...
Download data including ItsDeductible (if used previously or during the year before it was shut down in October):
https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/access-manage-persona...
