Make the most of your Flexible Spending Account! There is a 75-day grace period for all 2017 reimbursable expenses. This means that you can still claim services received in the first 75 days of 2018 against your 2017 Flex account. The deadline for filing for 2017 services is March 15, 2018. These claims should be sent to ProBenefits by fax at 877-329-3539 or email at email@example.com. You may contact ProBenefits at their toll free number: 1-888-722-8382.