Beware! My Sales rep, Brennan, got me to sign a co...

Beware! My Sales rep, Brennan, got me to sign a contract for installing solar panels by promising is would be done in 2019, making me elig for the 30% tax rebate. Next they moved the installation to Dec 31, 2019. Then on the night before install called and rescheduled to Jan 2 2020, dropping rebate to 26%. Reason: busy with another job
Then on Jan 2 texted We have 2 installers out sick today because of that we are not able to install. Not a damn thing I can do about it because I relied on their verbal assurances.