Is the plumbing sudden broken covered by the home insurance?

[Ray X.]

My house pipe under the concrete was suddenly broken last December that causes the water damage. My home insurance pays for the water mitigation and rebuild but refuses to pay for the plumbing repair. The plumbing repair invoice is about $2500 in Excavate concrete/Difficult Access, Performed pipe repair and backfill and tamps/ Repour concrete. Can any expert advise how to argue with the insurance and let them to pay for the plumbing repair or the plumbing repair is not covered by the home insurance? Thank you for your answer.