That is completely irrelevant, Tiger, don't think for a minute it matters whose account it went into.
The facts are
You have lived for 15 years as a non-paying tenant in a house belonging to your ex-in-laws, because they didn't want to take rent from you. IT'S STILL THEIR HOUSE NOT YOURS.
You split with your husband, they want their house back.
Your witness to this alleged verbal promise is a relative of yours, you already said that, so the witness evidence won't hold water as you are related.
The "promise" was to you and your husband, not to you on your own - and they want you out.
If anything, the disadvantage is your in-laws, because of all the rent they could have had over the years if they had had paying tenants in the house - they have lost out financially, big time.
As I said ages and ages ago, what you and/or your husband paid for work to the house is IRRELEVANT - we all do that, it's not a credit note for future ownership, otherwise I'd be owning several rented flats by now where I lived in the past.
You and yoru husband were foolish in the extreme not to get the promise in writing. You have NO CASE, as others have told you many times. Why give me best answer if you don't believe you are heading for financial ruin if you take this any further. Think of your children's welfare, not your own selfish gain to stay in the house. Go to the housing department, tell them you're being evicted, and MOVE OUT.