There is a challan in the statement which was unconsumed will I be able to claim the refund for the entire amount?

Refund can be claimed as per 'maximum available balance' i.e. Challan amount minus maximum amount consumed in any statement for the particular Challan.

Scenarios 1 Challan Amount =1000: Amount consumed / claimed amount = 500, OLTAS Available Balance = 500, Refund amount will be: 500

Scenarios 2: In case deductor modified deductee rows of Rs 100: In such case,

Challan amount 1000:

Challan consumed / claimed amount = 400,

OLTAS Available Balance = 600,

Refund amount will be: 500 (Rs 1000 Minus Rs 500)

Scenarios 3: In case deductor Add deductee rows of Rs 100: In such case,

Challan amount 1000:

Challan consumed / claimed amount = 600,

OLTAS Available Balance = 400,

Refund amount will be: 400 (Rs 1000 Minus Rs 600)

Scenarios 4: In case deductor again modified deductee rows of Rs 100: In such case,

Challan amount 1000:

Challan consumed / claimed amount = 400,

OLTAS Available Balance = 600,

Refund amount will be: 400 (Rs 1000 Minus Rs 600 (Amount consumed as per Scenario 3))