Helimax 200 fp problem!!!! PLEASE HELP.

[Nathanm22287]

Hi I bought a Helimax 200 fp about a month and a half ago and was in flight when a mixing arm came loose I replaced it and went to fly again and it would lift of and go straight backwards till touching back down while at idle on the ground the tail would spin to he right even when trimmed. Well I brought it inside and weighted it down to power it up and look at it.. Now the main rotor just stays at full throttle even when remote is turned of I can't find any related problems on here so please help me I'm lost...