rocktron deep blue problem

[Ielia]

Hi friends, first time posting here 
I'm not sure it's the right place to ask about it but I will go for it. 
I got rocktron deep blue, it seems great inside, like mint condition, but yet there is 2 problems with it.
First one is it work some times, but some times not, I need to click its button like 3-7 time for it to start the effect (led do turn on).
Second is in the rate pot... has no effect on the sound at the 0℅-75℅ at all, 75℅ and more its like full rate.
Anyone had this problems? Some advice? What can I do to fix it?