Q: If my previous landlord failed to notify of inspection, and failed to mail out the paperwork stated, what can I do?

A: I've pasted below Missouri's security deposit statute. You could sue for twice the amount wrongfully withheld but, based on your post, you should expect the landlord to file a counterclaim against you.

In addition, if the lease has a one-sided attorney's fee provision, as most do, if you litigate and lose you will be responsible for your landlord's attorneys' fees.

Security deposits, limitation--return of deposit or notice of damages, when--withholding deposit, when--tenant's right to damages--security deposit defined.

535.300. 1. A landlord may not demand or receive a security deposit in excess of two months' rent.

2. Within thirty days after the date of termination of the tenancy, the landlord shall:

(1) Return the full amount of the security deposit; or

(2) Furnish to the tenant a written itemized list of the damages for which the security deposit or any portion thereof is withheld, along with the balance of the security deposit. The landlord shall have complied with this subsection by mailing such statement and any payment to the last known address of the tenant.

3. The landlord may withhold from the security deposit only such amounts as are reasonably necessary for the following reasons:

(1) To remedy a tenant's default in the payment of rent due to the landlord, pursuant to the rental agreement;

(2) To restore the dwelling unit to its condition at the commencement of the tenancy, ordinary wear and tear excepted; or

(3) To compensate the landlord for actual damages sustained as a result of the tenant's failure to give adequate notice to terminate the tenancy pursuant to law or the rental agreement; provided that the landlord makes reasonable efforts to mitigate damages.

4. The landlord shall give the tenant or his representative reasonable notice in writing at his last known address or in person of the date and time when the landlord will inspect the dwelling unit following the termination of the rental agreement to determine the amount of the security deposit to be withheld, and the inspection shall be held at a reasonable time. The tenant shall have the right to be present at the inspection of the dwelling unit at the time and date scheduled by the landlord.

5. If the landlord wrongfully withholds all or any portion of the security deposit in violation of this section, the tenant shall recover as damages not more than twice the amount wrongfully withheld.

6. Nothing in this section shall be construed to limit the right of the landlord to recover actual damages in excess of the security deposit, or to permit a tenant to apply or deduct any portion of the security deposit at any time in lieu of payment of rent.

7. As used in this section, the term "security deposit" means any deposit of money or property, however denominated, which is furnished by a tenant to a landlord to secure the performance of any part of the rental agreement, including damages to the dwelling unit. This term does not include any money or property denominated as a deposit for a pet on the premises.