If the tenants do any maintenance work, and expect a reimbursement for it, they need to first take approval and share a quote before starting the work.
Only after the quote is approved, can they do the work.
But if they have done some work without approval:
1. Please check if the work falls into Major / Minor category:
https://property-angel.freshdesk.com/a/solutions/articles/44002534939
2. If major (or should be responsibility of the owner), please check with MNT counterpart, if the Bill is reasonable.
3. Only then share the quote with owner and request for a refund.
4. Else, please reject it or you can request the owner for a partial refund.