Reliance Smart Bazaar - Behaviour and Wrong price Tag Issue

Dear Concerned,
Want to escalate an issue which happened today with me.
I am a regular customer to Smart Bazaar, Main road, Ranchi and today when I did shopping, saw the bill then I found that I was being charged extra than the tag amount. I asked for this from the person at the cash counter and his reply was that it is old tag but now the price is higher. I asked what is mu fault in this and I asked for refund. He informed me that refund is not possible, I will be provided credit note and I will have to go to exit gate, then come again from entry gate, then need to issue exchange then I will get Credit note which is valid for * months.
What kind of service and policy is this?
When I was at the counter only when I highlighted this, why I was asked to go to exit gate to exchange? Moreover why will I get the credit note and why not my paid money?
First, you did not put the product with correct price tag and billed me, charged me for that. Later you are telling me to exchange after going to exit gate and come again from entry gate? Secondly I will be provided credit note, WHY? Is it my fault that you did not put the correct Tag and when I am highlighting immediately, then also you are asking me to come again from entry gate?
Then I asked for manager. The person called another person from nearby counter and that person also told me that credit note will be issued and he told us that this credit note will be valid for * months. Then the my counter person corrected him that it is valid for * months.
The staffs are not aware of the actual policy and there is a clear knowledge gap between them, Don't know how they are being trained or such a big brand is running by such staffs.
Later, Manager (Shyam) came and he told me that credit note is the only option. Then he called his senior (Farhan, may be). He also told the same thing about credit note. 
Then Manager Shyam's tone got changed suddenly. He told "apko lena hai ya ni lena hai, ek baat pe rahiye". Is this the way a manager or any staff should speak?
How can this type of person be a Manager? I am also working as a Manager and I know better how to behave with customer? Not at all like his tone and behavior?
Then Farhan asked us to show where price is written INR *** (we got charged INR ***). We went there and found the same price (INR ***) and no such price mentioned which was charged from me. The his excuse was that some other customer might have misplaced it in wrong place, I asked him to show the actual price where it is written? But that price was nowhere mentioned which was charged. Then his another excuse was that we have so many stocks from *-* days and we are placing it due to which old price must have mentioned there. He also mentioned that "We cannot place staffs everywhere to check this".
Is it my look out as a customer to check if the correct price tag is mentioned or not? Or is it yours and your staff normal job to check this? Are you expecting that a customer will check this?
This experience has really brought me in a situation to think how such a big brand is running? On these managers who doesn't know how to work? Who are blaming customers for their inability? 

I really need an answer for this - 
*. Is it customer's fault that price tags are not updated correctly?
*. How can a manager speak in rude tone?
*. Why a customer should accept credit note when customer is not at fault?
*. How can a senior manager tell that they can not update the tags properly and they are over occupied?*. How can a manager blame customers for their mistakes and not doing their work properly?
*. Why is there different knowledge about the policies among the staffs?
*. Why will a customer go to exit gate to exchange a product when customer is at the cash counter and escalating this on real time?

Regards,
Neeraj Kumar