Wheres the TMNT comics?

When I use this app says " unable to connect to the comixology store". I want to get some tmnt comics, can any one help me with this? Where can I purchase some? I already used IDW app and there is no TMNT comics in there either? Is anyone having the same trouble? Is because I have iPhone 4S?
Tmntfan

Tmntfanjay about TMNT Comics, v3.1.4