How to avoid the lock pulling away from body.

Hi everyone here, I just bought and joined the CB world
some questions and problem here for help.

I started wearing it and was in my third day, and the model is holy trainer knockoff.
got no problem putting it on the first day.
but still always wonder if it was suitable for me or not,
because my penis can actually reach to the end of the tube,
so i assume it is okay with length.

Apart from that the biggest problem for me now on is the cage pulling.
it still allows my penis to go half ercect in the place before the ring,
making it very uncomfortable when walking and visually ugly in pants.
I have tried to re-lock over and over again, but it stay the same.

I search few threads that people asking the same question.
but no one really seems to solve the problem and report to it.
The common answer is to change the ring sizes which I have done yesterday.
so I am confused now, for your knowledge are there any other factors to cause this?
and should I bought and new one? first posting here, so your help will be very appreciated
Thank you. and I am sorry for any English mistakes.