Seller delaying registration

I have planned to purchase a commercial property for our own official use & then rent it few portion for loan repayment. I have found a suitable property & the seller has purchased this property in 2005 which is registered in Husband & Wife name.We did an advance in end of January & made sale agreement in March.There was BDA sale deed issue with this property which is mentioned in sale agreement,which is not sorted yet.With this issue we are unable to get loan on the property.So we created new sale agreement in September with 1 month valid without adding the BDA issue.Now our loan is sanctioned. We are ready to register the property ASAP, but seller is delaying for many reasons. Below are the new issues for there delay:- 1.Tenant is asking some money as goodwill, with 5 to 6 months duration to vacate. 2.Seller has separated with ego clashes and Wife is delaying for unknown reasons for registration. 3.Her sons are abroad are not signing coming for registration. If seller agree for registering the property within 2 weeks what are the clauses should be added in the take over agreement for tenants until they vacate. If seller still delaying to register, should i ask for refund ? We have mentioned the clause in sale agreement for "seller shall pay reasonable damages, along with the advance amount to the purchaser" if breach from seller. As per seller request, we have paid 20 Lacs as advance amount with part payments after creating the sale agreement.