Washing machine dispute

Maintenance

Hi, Appreciate your advice....We are new to this only having full-time tenants since February. They have reported that the washer drier is leaking and the repairman told them that the drum had been pierced. I have googled this on google and it appears that this is caused by a "foreign body". Something that should not have been put in the drum. Prior to full-time tenants we had the washer installed 2 years ago for use by our Airbnb clients. There were not many as the season is limited. Also people who come for the weekend are unlikely to want to do their laundry. Our tenants who are protesting innocence (my interpretation) have been there 5 months and the washer has not leaked. They probably don't want to pay for repair or replacement and we think it likely that it was a mistake that they have made, albeit unconsciously. I suspect that it will be hard to prove but your advice would be welcome. What do I do next?