Tell (and write to them) (be polite), stating that you are having lots of problems with logging in – they will be pretty overwhelmed with that problem and used to it.
They will put a record on their system and may even call you back although if you have, quite rightly, refused access to them, they won’t be able to help. The User ID and the complicated password system is a right pain. If you don’t know your User ID, you could ring up the DWP and they will forward you another by post, which can take several days! This is supposed to be ‘for security’. However, as the jobsmatch is not compulsory, they just want evidence that you are using it (if it is part of your Agreement) so print a few copies of jobs on Gov.uk and if you are at a job club, get them to sign the copies as well as an extra to show you are actively looking.
Universal Job Mismatch 
I will provide an overview of two of the most common type of computer printers; the ink jet and the laser.
They can print up to 22 ppm (pages per minute) in black
and white at 1200 x 1200 dpi, and up to 18 ppm in color at
4800 optimized dpi. Compared to earlier consumer-oriented
printers, inkjet printers have a number of advantages.
im finding loging in to universal jobmatch very hard today it wont let me log in
m finding loging in to universal jobmatch very hard today it wont let me log in
Try going on Incognito in Chrome