In my opinion any software company sells as specific software for specific price which must work for unlimited period of time. There is no question of renewal of any kind of warranty as such to give service/help to maintain working condition of that particular software.
Once can charge or go for renewal of subscription only for new arrivals or continual upgradation of software. AND NOT FOR WORKING CONDITION OF PREVIOUSLY SOLD SOFTWARE.
IF THE DATACOMP webtechnologies ltd insisting you to pay for reinstalling of your own old version of software is wrong.
I also experienced with them same way. The made it such a way that the softer ware will not work properly or not at all work immediately after one year of purchase or one year after payment of their so called renewal charges. After big fight with their Mumbai Head office they sent me required code number for activation.
You please approach consumer forum for this. In general principles of law/business this kind of conditions will never hold good.
Once can compare the same kind of issue with similar type of company. for example if we buy Tally software (accounting software) which is working unconditionally for unlimited period of time. They demand for subscription only in case of major up gradation is required. I appreciate them for ever.
At the same time cursing this kind of substandard business practices of DATACOMP WEB TECH