strut threads?? help needed!!

[billinjah 0]

im still struggling with these damn strut mounts the collar that holds the strut top mounts on will not thread onto the strut i thought the threads were damaged but there not they look flat rather than pointed at their peak but im told they are supposed to be like that?? the nuts that hold the top cap on thread on fine and these are supposed to be the same thread. the collars were an absolute b**tard to get off in the first place ive checked and double checked the part numbers. the shocks are avo coilovers that were on the car when i brought it. do you have to heat the the collars up? i asked darren at gwerks about this and he thought the collars must be wrong but there the right ones for a g60 are the vr6 ones different? in case someone has put vr6 shocks on my ride! any help would be so much appreciated as ive had the car off the road for a week because of a jpb that should take 10 mins!!!!!