When your father agreed to buy single premium policies he must have signed the proposal form and kept copies! He must have paid by cheque/cash and must have received the acknowledgment in his name! Do you have these?
If your father signed blank proposal forms then who filled the forms? There is a column to declare that who has filled the form say agent?
In policy schedule the copy of proposal form is to be attached. Do you have these?
AS a nominee were you asked to sign the proposal forms? From which source your signatures were acquired? How come your KYC docs were obtained by agent?
Then there are internal declarations to be signed by agent and company’s employee’s that they have seen the originals and marked OSV! Then there are calls by Third parties to confirm the authenticity of the proposal form was signed and there is no forgery!
This is a case of forgery.
Criminal complaint and complaint with regulators can also be lodged.
The company shall face severe penalties and compensation.
You should not be satisfied with just refund of premium.
Certainly approach an able lawyer.