What can I do when I received a 1099c for 2019 on debt they wrote off in 2014? Then I could have proven the insolvency issue. they picked a random 2019 date.

[AlexanderS08]

Generally, insolvency is analyzed at the time the debt was forgiven. 

Although we cannot provide legal advice, you might consider speaking to a CPA or Attorney who can help you file an amended return for the year the debt was actually forgiven. If, hypothetically, you filed a prior year Form 982 and then many years later received a 1099 for that same income, you might be able to explain to the IRS that you already included it and excluded it in a prior year so that it is irrelevant.

In any circumstance, you will likely need to communicate the issue to the IRS which is why you should consult a CPA/attorney.