First, I do not understand if you are on leave for one month, does that mean you stop to breathe, eat, and sleep? At all times, priorities and urgent matters need to be attended to. It is surprising when you mention working in software—individuals in your field often show up with laptops like pets. Therefore, why not send the proof by email to the company on time? This only shows carelessness or a lack of value for yourself, your time, and your priorities. First, set things in order, which will go a long way in your life.
Regarding the Income Tax Investment Proof
It is mandatory for the company to set a deadline to accept it, as per the law requiring such provisions. TDS is mandatory for the company as per IT regulations, and therefore, all proofs should be with them before they provide credits for such investments in the form of deductions from total income or tax deductions, as the case may be for those investments.
Every employee should adhere to the company rules and follow them. When HR or the Payroll management is responsible for calculating the IT for multiple employees, it is not feasible to make frequent changes.
Nonetheless, you have not missed the bus. Once the company completes its IT calculations and if any TDS is to be deducted, they will do so and provide you with the necessary certificates according to IT rules. You must then file your return independently, and if there is any refund due, it will come directly from the Income Tax Department.
To reiterate, every company circulates forms asking employees to outline their investment plans, eligible for tax deductions. Typically, this is done every three months to cross-check planned investments with actual ones, by providing proof for such investments made and to be made. Therefore, it is crucial to plan your income and investments monthly before receiving your salary. Keep copies of the form provided, your payslips regularly, as well as your investment proofs to avoid delays.
Good Luck.