Lost Mode Alarm continues - I found my iPhone 5!

Hi. Last Saturday morning I lost my phone and immediately went onto iCloud and entered the phone into Lost Mode, sent the message and Played Sound. Spent all that day reporting the loss to the police, insurance and Vodafone and generally panicking. Went to bed that night, put hand under pillow and guess what, found my darling phone!!! What a relief!! Cancelled Lost Mode on iCloud and restored passwords, Vodafone etc. HOWEVER, at various times (and obviously I never get any warning), the lost alarm still sounds and in public, people must think I have stolen my own phone!!! I have tried different ways to stop the alarm happening again eg setting Lost Mode over again and then cancelling it again but the alarm still goes off. All I have to do is press the on/off button to stop it sounding but the fact that it goes off in the first place is the problem. It should be cancelled!

Why does the alarm still go off? Can anyone help please?

Many thanks

Susan 😕