Page titles of my Store are showing some junk data in Google SERP, why is that happening?

Google adds some random data in the page title of your store if the page titles are too small or too large, usually, it adds up the first text that it receives on your website.

For more details, you can refer Tips for Store/Page Title.

In your case, the page title is too small (eg Kids, Trucks, Teethers etc), hence it has appended them with your customer care number. 

To prevent such issues try to add the meta title of the page of upto 45-55 letters so that the title is not too small and Google doesn't need to add further random data.