Hi,
To avoid any disallowance in future, you can pay Rent through Cheque after deducting TDS of 10%.
You have already paid rent for four months and might be TDS return already filed by firm on quaterly basis.
If they have not yet made rent agreement , pl suggest them to prepare rent agreement and deduct TDS @ 10% from Aug'12 rental payment on Rs. 200000 ie you can deduct 20000 TDS and deposit TDS accordingly.
or you can suggest landlord to prepare rent agreement and sub divide rent into 3 persons equally so in this case no TDS would be required to deduct as threshold limit will not be crossed Rs.180000 per person per year.
You have to mention Rent aleady paid to three different person of family of this landlord accordingly In this you can say that you have not in default.
You have to change name of person in your books of accounts to three person to avoid any TDS issue.
Regards.
SKV