Hi, if you contact support while having cheated energy, coins and gems etc. you will get banned 100%, you can try to reduce them via game guardian but im not sure they cannot still detect some form of cheating. At this moment im not aware of a solution for that bug so, your best bet, is to contact them or wait indefinitely for a fix.
For attributes try to use the "unkown value" button and after that refine with the N = 0 + D, it works everytime.
For that old account, the answer is yes but you need to keep attention of what you are doing because for gems and coins you need to change the total sum of coins and gems earned not what you do have right now and make sure to not go too far because if you end with a negative value your game will break.
Edit: for your character level try to give a look at this chart XP Level, try to find, more or less, your xp and after that go to game guardian and for example write 4000~5400 ( if you are around level 9-10) and after that refine with the unknow value N = 0 + D while gaining exp.