Implicit in your post seems to be that you entered into either a written forbearance agreement or a written modification agreement. If you are instead describing entering into an obligation for an original promissory note at a regular loan closing, then the post doesn't seem to make much sense.
I would first point out that Mr. Roper and others have mentioned in several prior threads that servicers very often present a borrower with a written forbearance or modification agreement calling for signatures of both the borrower and the mortgage investor which the borrower is encouraged to sign, but which is NEVER actually signed by the lender.
If you negotiated an agreement with the Lender and YOU signed the agreement and presented a check, but the Lender did NOT sign this agreement, then you probably have NO AGREEMENT WHATSOEVER. To the contrary, where the agreement contemplates the signature of both parties and one party does NOT sign, then there usually is NOT AN AGREEMENT.
In general, mortgage transactions everywhere tend to be covered by a state's statute of frauds. Sometimes, the note is covered by the statute of frauds, as well.
As far as I know, ALL states have laws called statutes of frauds which pertain to the sale or lease of interests in real estate, requiring such agreements to be in writing. This includes mortgages and deeds of trust.
In some states, the statute of frauds also expressly covers contracts involving amounts of greater than some threshold amount (e.g. $50,000) or the performance of which is contemplated over some time horizon exceeding a certain threshold (e.g. - performance is contemplated to occur over more than on year, etc.).
So if a state has a provision bringing contracts for a value exceeding $50,000 and performance of which is contemplated to be in excess of one year within the statute of frauds, then a thirty year promissory note for $100,000 would be subject of the state's statute of frauds in addition to the mortgage being subject to the statute of frauds.
Each instrument probably also has some provision indicating that it is the entire agreement, that it can only be altered in writing and that no forbearance would alter the agreement or waive a right to declare default. Such written provisions are very likely to be enforced by the courts.
The bottom line is that UNLESS you have a copy of the modification agreement executed by the mortgage servicer or mortgage investor, YOU DO NOT HAVE AN AGREEMENT.
So BEFORE you start meditating about what sort of breach of contract provision you might seek to assert, you are going to need to prove that THERE WAS AN AGREEMENT. If you have ONLY THE ORAL REPRESENTATIONS OF THE LENDER or an agreement SIGNED BY YOU, but UNSIGNED BY THE LENDER, you probably have no agreement and no cause of action for breach at all.
Re-read your note and mortgage about five times. Carefully read the language of the modification agreement and LOOK FOR THE SIGNATURE of the Lender's representative.
Only AFTER you find that you can prove a contract ought you be thinking about how to plead a breach.