We recommand that you buy your tefillin and mezuzot directly from a certified sofer (scribe) there seems to have an issue with supply system for all tefillin and mezuzot that come from abroad in the level of how kosher they are.

Here's a list of sofrim that have been trusted by the KLBD

lawrence judaica

Shabbos

Prayer Books

Judaica

Books

Game & Toys

Cooking

Lawrence

Rosh Hashanah

Succot

Chanukah

Passover

Purim

Customise

Checking 

Lawrence Judaica LTD 

 Reg No. 10572265