PnP on Darwin - what a disgrace

We baught a soda stream gass bottle on 11 September 2020 at about 1pm at PnP on Darwin. At about 7h40 pm that same day, i opened the gass bottle, broke the seal to insert this in our Soda stream. Turns out, PnP has yet again dissapointed us. The gass bottle was empty. We went back to this PnP this morning, 12 September 2020 to exchange the gass bottle, taking along with us the plastic that sealed the bottle and the slip to prove that we had baught this bottle from this PnP. A lovely lady, Adel, assisted us, but seeing that she cannot make the decisions, she called the store manager that was on duty, Darren... Darren did not even introduce himself to us, all he said was, that he cannot give us a new bottle as they need to send this bottle back for investigation. This is a gass bottle that we already paid for. We werent offered our money back or given a new bottle. We were advised that we can leave our details with the store and they will contact us when they have received feedback. My husband advised Darren that he paid for this and he wants what he paid for, but Darren, did not want to hear anything. There was no way that we, the customers, were right and for him to give us our money's worth. We then had to leave the store without our gass bottle and R250 less. I am sure that Darren could have apologized and given us a new bottle and investigating it with his supplier after he had satisfied his customer. But ofcourse, the customer is always wrong and trying to strike a deal. Darren, i can assure you that we did not lie about this gass bottle and that we did not use up all the gass in one night, these gass bottles normally lasts about 4 months in my house. This has not been the first time that we have had terrible service from PnP, but it sure is the last. PnP will not see us, or our Monthly groceries money again. I am absolutely appalled by this service.