Dear Nisha,
When we pay advance, it means first we deduct the TDS and paid the balance whether it is billed amount or advance whatsover. So you paid advance after deducting the tax. So this is your statutory liability to deposit the TDS.
Secondly, you have to communicate with that firm and kept the communication record for further proceedings. If you wish to go legally the it would help out. Without any communication record, you cant go for write off the amount.
I would not suggest to write off the amount immediately.
Regards,
Sandeep