Can I get charged if I left out a bag to be picked up and am I liable if they took ages to come pick it up?

Recently, my friend left the country and asked me to keep a text book of hers which I obliged and I've kept at mine for safe keeping. I also have a t-shirt I borrowed off my friend and a piece of makeup I took accidentally when visiting her one day (which I told her I had as soon as she asked and I checked). They were chasing me up for 2 weeks to meet up with them but due to family issues and work. I never had the time to go to the city to return the items. So we decided that I would just leave the bag out to be picked up. I put it outside my old address as it's done the street. My family have a baby in the house and we didn't want them knocking on the doors at all hours of the night. However, they took over 18 hours to come pick it up and by the time they arrived, the bag was gone. I even messaged them again to tell them to come soon as it was just left out in the open but they didn't come until the night time when it was left out the night before. Now they're accusing me of theft and saying I never put it out. I still have the items and are saying they're going to the police and the messages where I admit to having the items (there are also messages where I agreed to return them, I never once said I wouldn't) can be used as evidence to get a warrant to search through my house. They also sent me threatening messages insulting me and that I should watch my back when I was nothing but polite the entire time. Would they actually be able to get a warrant? The items are worth maybe 200-250 dollars max, probably even less. I'm just not sure what the police would do in this situation in all honesty.