depends how your TA is drafted. Usually my TA mentions the tenant will pay for the legal fees if they have a default on their part.

To take action against them make sure u have sent them at least 3 notifications (with the Tenants acknowledge receipt) on their delay in paying rental. After 3 official letters sent, u can goto any legal firm and proceed to ask them send a Letter of demand(LOD). If they were to pay after the LOD then they will have to pay for the legal charges as well for issuance of the LOD. If they still dont pay you can bring this matter to court, u will need court order together with a bailif to evict them.