Orvil is correct; your insurance company should cover the damage and inspect for any mold remediation needed. If they pay for repairs, they will surrogate against the landscaper to recoup their money.
I think you need to speak to the ARC. There is something in the restrictions that state:
B. IMPROVEMENTS SHALL NOT BLOCK, INTERRUPT OR REDIRECT ANY EXISTING DRAINAGE FLOW.
C. IMPROVEMENTS SHALL NOT CAUSE ADDITIONAL DRAINAGE FLOW ON ADJACENT PROPERTIES.
D. PROPERTY OWNER IS LIABLE FOR ANY RESULTING BLOCKAGE, INTERRUPTION, OR REDIRECTION OF
EXISTING DRAINAGE FLOW, ANY ADDITIONAL DRAINAGE FLOW OR ANY TYPE OF EASEMENT
ENCROACHMENT(S) ISSUES.
See bottom of page three.
https://www.districtgov.org/departme...pplication.pdf
I expect you can file a complaint with the ARC and have that mulch fixed, avoiding further damage.