Pnp not as good?

I went to withdraw money at there till point as it does not cost me money. It went threw then all of the sudden decline. So never got my money. They told me to go to my bank to get it reverse. So I went then the bank told me i need the decline slip which they never gave me as they hold it trying to find out what went wrong. So I went back to pnp just to get told they dont have the slip they threw it away and there trash already went sent out and picked up. The bank needs that so they can look into the whole thing to reverse my money. Now i can not get my money back as they threw the slip away. This happend threw a manager and there supervisor.