Damaged tomstone costing us R 19 400.00

We bought 4 tombstone from JB granite, of which 1 has fallen within 3 months after installation which cost us R 25 000.00. and the other has not yet fallen but the top/header is loose which can fall at anytime. We requested the supplier to come and do inspection on the damaged tombstone, they did not come but now they want us to pay R 19 400.00

We have been communication with them to come and investigate and