How to do higher studies in Mathematics if you are in IT Company?
You have not mentioned what is your background, i.e, what is your graduation stream.
If it is either Maths / Statistics, then you could do higher studies like M.Sc Mathematics. Check out the colleges offering M.Sc Mathematics courses on the same.
Also, since you mention you want to work and study, then distance education could be more suitable for you.
Universities like IGNOU, Anna University etc., could offer M.Sc Mathematics courses for distance education.
However, if you are not from Maths/Stats background, it would be difficult to get admission for higher studies, as the eligibility is mostly B.Sc or BA in Maths / Stats, or B.E./Tech.