RERA Complaint after possession regarding penalty , Electric infrastructure and Labour Cess

1.Builder has promised to deliver me a flat by Mar 2020 with 6 month grace period , As per his payment schedule i was supposed to pay all the amount of the flat by 15 Jan 2020 as i booked flat on 1 Dec 2019 so with in 45 days i have to pay him 90% Amount . I paid 10% amount on 11 Jan 2020 and asked for allotment letter and request them to cancel the flat but they denied and told me to get 20% Amount more and only after 30% i will get Builder buyer agreement some how i arranged this by 15th feb 2020 and gave them and got allotment letter on 24 Feb and after that i applied for loan and my loan was approved on 20th March but as lock down happened i was unable to pay the payment till June and August . Builder has charged me a penalty of delay payment 50K is it valid ?though i was just late 24 feb to march but point is i got BB letter late from them because they ask 30% which is not Rera rule . 2.In Builder buyer it was written that Electricity load / electricity meter will be borne by Buyer and no where amount was mentioned when Signing i asked what are these electric charges i was told that these are the charges i pay to UPPCL ,Later on builder asked us to pay 71K saying electric infrastructure no where in builder buyer this term was used .