You say the machine tuns continuously as soon as you connect the pedal. This appears to be a regular fault.
You give the serial number of your machine but not the model.
This may help, however you will need to check it is correct for your model of machine:
please note the comment about finding someone technically competent to do the job. It is easy enough to do.
Actually, if you are competent to just get the component and do the job without instructions (or know someone who is), this may be suitable:
Alternatively, just do a Google search for "Singer Pedal" to find suppliers of spares and buy a complete new pedal