my 12 inch trimmer is not working. HAve used and love it but had weeds wraparound under the trimmer head., Removed the trimmer head and with much effort removed the debris but may have removed a gasket. Need to know if I did because after replacing the triimmer head it does not sit well on the post and is crooked. Can not find my book on the trimmer to see what is wrong. I am 82 years old and not too mechanicaly inclined but aware that I may have removed the gasket under the trimmer head which I believe may have melted from long use and the debris collected under the head may have adhered to the gasket Need to know what to do to get the trimmer working. does a great job when working . Tried to call to speak to someone but waited a long time and did not speak to anyone., that is why I am contacting you on line. Please respond.