Why would she text me then make up some story?

My ex texted me yesterday and message me on fb i was a sleep when she texted me so I sent her a message back today just saying hey hope your ok always here for you you no that she said she was going through some stuff. Then she came up with some story about get mum using her old iPhone I no her mum isn't that thick to use someone else's fb account she's very bright when it comes to stuff like that not like most people her age so why would she text me and message me on fb then say that?

She was drunkin dialing do not worry about she texted me to last nite