[Konstantinos]

Using timers is a bad idea. It's better using unix timestamp:

pawn Код:

// global
new Cmd_Timer[MAX_PLAYERS];

// OnPlayerConnect:
Cmd_Timer[playerid] = 0;

// in command:
if (Cmd_Timer[playerid] && gettime() < Cmd_Timer[playerid]) return // error message about waiting
// code from the command and in last line:
Cmd_Timer[playerid] = gettime() + 1200;