Interest on Delay in Loan Disbursal being Charged by the Builder

I purchased a 3BHK flat in Luxuria Estate, Aditya World City, Ghaziabad under a scheme of 10:80:10 where the 80% of the amount was financed by IndiaBulls Housing Finance Limited. Note that, in all this booking and transaction, Investor Clinic was involved as the agent. When I tried to contact the builder directly, they mentioned that they have exclusive tie-up with Investor Clinic and all the flats are currently being sold via Investor Clinic only. Now, the representative from Investor Clinic put an incorrect flat no. in our booking form while he communicated some other unit number to us. It came to our notice at a later stage when we'd already paid the initial 10% amount. Now, after discussion, the representative confirmed that the unit can be changed an got a new booking form filled and signed. This process took around 30-45 days. Now, due to the change in unit, there were some additional charges which we paid as soon as the change of unit was confirmed by the builder. Further to that, for the next 80%, we'd the option of only one bank which is IndiaBulls as Investor Clinic, Aditya Group and IndiaBulls had a special agreement among them. So, I asked the Investor Clinic representative to get the loan processed. However, he kept on dilly-dallying it for several days citing reason that I am awaiting some kind of approval. Later, the company processed the loan at a very slow pace due to the inefficiency of their Sales Executive who didn't know as what documents he needed to collect to process the case in one go. Thus, the entire process took around 2 months. Now, when I visited the builder's office to make the final payment of 10%, he claimed that I owe an additional amount of around 2 lacs due to delay in : a) Payment of the additional amount due to change in unit (The date was calculated from the original booking made for the incorrect unit) b) Delay in loan disbursal by the bank. Note that I wasn't aware at all that this delay by the bank shall cause me any sort of penalty. Further, the information about this penalty amount should have been shared as soon as the payment was made but the builder kept it a secret and disclosed it at the time of final payment only. Kindly suggest as what action may be taken in this regard.