A copyright is infringed if any three lines of the software are similar to an existing software as per Copyright Amendment Act, 2012. What i fail to understand here is the following: "You say the software that you developed has a similar feel and look of an earlier software and then contradict yourself by mentioning that you have used codes which make your software different". Now, either your software is entirely different or similar. So, in this context, first thing you have to analyze if your software is different or similar in any respect to the earlier software.
Further, I might provide an example here. Lotus spreadsheets are similar in feel and look to that of MS-Office but both co-exist because they have entirely different functionality. If I read your question correctly, then I believe what you are trying to say is somewhat akin to the example I have given here. If that is the case, then you need not worry. You have a strong case on your part.
If in the software you developed, there are three lines of code which is similar to the earlier software even though you have used a different platform of OS and programming code, then you most probably infringe the earlier software.
Since the suit has been filed, you can contact my partners Mr. Sagar Chandra on +91 9811970271 or Ms. Diva on +91 9899881575 for filing a proper reply.
Please be advised if proper reply or proper representation is not made, then there is also a probability of compensation that may be directed by the court.
I hope the above helps.