Delhivery - Package not delivered

I came to hyd on **th Feb and i forgot to bring my charger with me so i decided to buy a new charger when i check online it prices around **** Indian rupees so i thought why to waste money instead i can use any courier service so i can get my charger to me.Then i created a shipment with delhivery courier on *st March and the pickup is done on *rd March and they updated est delivery date is *th March.After that my parcel has reached my nearest hub bhel_hyd on *th March then i thought they will surely deliver my package on time which they didnt.On *th March evng they rescheduled the delivery that's the only update that's showing in the delhivery tracking portal till date.est delivery date keeps on changing daily.
I even visited my nearest hub bhel_hyd for *days continuously on *th,*th and *th.
When I first visited there they promised me they will definitely deliver my package on next day morning which didn't happened so i revisited again on next day evng so again they came up with same exact words that they said earlier so i asked for self pickup then they said we have lot of packages we need to check it's not possible to give it now and also added please trust us we will definitely deliver it tomorrow and obviously it didn't happened.I got frustrated and revisited again to that hub then they showed their real faces instead of giving me a solution they showed bad attitude towards me. I got very irritated and left immediately.out of frustration i tried to cancel my shipment in delhivery portal then it showed up like its not possible to cancel your shipment now if you want to cancel then dont accept the package when delivery person visits you.and meanwhile all this happening i also contacted delhivery on twitter,initially they responded and said they will deliver my parcel on top priority they said it on *th March after that i tried many times contacting them but they didn't responded.
I tweeted sent dm's and also sent mails but they didn't responded.
You know how much I got frustrated,they made me helpless.
Why is this happening why are they making it late? Is this because it's a individual courier shipment!?
Will they do same if this courier is from some ecommerce sites?
Is there any law that can help people like me?
Tracking Id:*************