I am sorry I cannot give you help with your exact problem but I can relate to having to get used to a new machine entirely, where everything seems new, at first you think you cannot do it, everything is in the too hard basket, and you want the old machine back which you new inside out! I gave my old manual machine to my daughter and I miss it as I could go a lot faster on it than having to look up all the instructions with the new one, which is SO different to my old machine.
Make sure you read your manual well and understand it, and that any attachments are the correct ones for your model of machine, and that they are attached in the correct way. Sometimes it is such a small thing which is overlooked which can put everything out, eg even threading the wrong way or using the wrong threads etc. I would call on your dealer if you have exhausted all these avenues. There are so many models out there even in the one brand of machine with various upgrades, not all are interchangable so you do need to familarise yourself with your particular model of machine and all that it is capable of achieving.