Pathetic service from ABSA Building Insurance

We logged a claim with ABSA for the sewerage pipe that pulled out of one drain gully at our house. There was clearly movement in the foundation underneath which caused the drainpipe to be pulled down and out of the gully. The plumber that came out to do the assessment also agreed that this was the case. ABSA though indicated that this was a maintenance issue and that our policy would not cover the costs to repair the drain. This is totally unacceptable!! How could any maintenance have prevented something that happened more than a meter underneath the paving? They are quick to debit your premium every year, but when it comes to paying out claims, there're always excuses. Poor pathetic service !!