Buyer negotiation in seller market

[Addam Simons]

Hello, I’m currently under contract for a live and fix property. The seller is aware of many of the issues with the house and is trying to work with me regarding up front costs of fixing the big ticket items. Mainly roof and septic. They have agreed to a 7k concession for the roof and a 3k concession for the septic. Both flagged in inspection as past life expectancy. Although now mortgage company is saying that those funds will only be held for 2 weeks. Likely not enough time to have them repaired. Provided the sellers won’t agree to just have them fixed, is there any other Avenue to try regarding these concessions? Thanks for your time!