Charged with 2 thefts from 2 shops, when I was detained in the second shop and did not attempt to leave without paying?

so a store detective said she saw me and my friend shoplift?...instead of detaining us she called the police which came to the second store, I was doing my shopping and was in middle of store when police stopped us and detained us...he asked if we had anything on us...my friend had her items in a see through bag in her trolley, which she does in EVERY shop...she gave them the bag and clearly stated she was paying for them which she had the means too!...any way both arrested on 2 thefts but we never left the store or had the intentions to do so without paying!...how can they charge us with that theft if we never left the shop with the items or without the intentions of payment as we clearly showed cash in our purse and offered to show how much was in bank accounts.