I am having major problems with no dero in wallet


i have not used for at least 4 months, my Dero wallet which i thought was web based . when i went to log in i got the attached message

since i could not log in i used my 25 seed word phrase which i had and then put in my passwords and that generated a wallet but had zero balance. i have a macbook pro and i have no idea how to add code lines etc.
i then tried to log into the older wallet “atlantic” which i am guessing is where my dero is held but again i could not log and this time my 25 word seed phrase did not work.
i gather from looking at other notes on this forum that this is fixable and others have this problem.
if someone could please assist me in the matter, i would be very grateful. i understand this needs to be fixed sooner than later or the coins will be lost.