[Nero_3D]

I see no major problem, so no clue but some minor problems

PHP код:

CMD:facpay(playerid, params[])
{
    // ...
    // you can combine the amount checks
    if(amount > 300000 || amount <= 0) return // ...
    // missing rank check
    if(!(0 <= rank <= 10)) return // ...
    // use arrays inside enums "fPay[10]"
    new idx = PlayerInfo[playerid][pFac];
    FacInfo[idx][fPay][rank] = amount;
    format(string, sizeof(string), "You have set rank %d's pay to %d", rank + 1, amount);
    SendClientMessage(playerid, COLOR_LIGHTBLUE, string);
    return 1;
} 


PHP код:

stock FACPAY(playerid)
{
    new pay[10];
    new faction = PlayerInfo[playerid][pFac];
    if(faction) { // rank as array like above
        strcat(pay, FacInfo[faction][fPay][ PlayerInfo[playerid][pFacRank] ]);
    } else {
        pay = "None";
    }
    return pay;
} 


Same with SaveFactions, change your variables to arrays