BC won’t act on common property (water membrane) repair

Shower leak reported by tenant mid May 2015. Took 8 weeks for Strata Manager / BC to get quote & 3 more weeks ( total 11 weeks) for BC decide they would only pay 50%. Reason finally given (after an extra week ) is ” As the property is professionally managed ‘someone’ would have known about it earlier and should have reported it earlier”. Have supplied Inspection reports which show that nothing was visible at last 2 ( 6 monthly ) inspections. And have supplied Tenant Reported Problems reports which also make no mention. BC is still not agreeing to pay 100% some 3 weeks on ( now 15 weeks since reported ) Fed up tenant has given notice as carpet in bedroom ( associated with bathroom wall ) is now rotting / mouldy / smelly. Next step?? How to get them moving AND what penalty / compensation can I possibly get as the damage is escalating due to their inaction.