Judging from the description of the defects on your new rifle, it deserves to be returned. Defects like you describe are unacceptable. Is your rifle new manufactured? Or one from existing stock? It is possible you got one of the earlier 'Remlins', that may still exist in dealer inventory. These were the rifles produced right around and shortly after Remington acquired Marlin. There were a lot of quality control issues with these rifles, during the changeover. If so, you can determine its manufacture date, using this process:
B=Jan Year: E=2010, F=2011, G=2012, H=2013, I=2014, J=2015, K=2016, L=2017, M=2018....etc. Note: This is for new Remington-made rifles. Prior to 2011(when the changeover in date coding started), Marlin rifles featured a number-code for
L=Feb Manufacture date. Ie: 91=2009, 90=2010, 89/Mr=2011...etc.
A=Mar
C=Apr
K=May
P=Jun
O-Jul
W=Aug
D=Sep
E=Oct
R=Nov
X=Dec
Any of the newly manufactured Remington-Marlins I've seen...especially over the past year, have really improved in overall build quality. Though quality control and inspection prior to leaving the plant still seems to be spotty. Still, if the rifle is newly manufactured and has the defects you mentioned, it should be returned for warranty. Gravel Agency is the warranty center for Marlin, in Canada. Ultimately, the choice is yours. The Marlin '94...especially in .357, is a handy, accurate and fun little rifle to shoot. Don't let one 'bad apple' sour these rifles for you. You may have gotten the one 'lemon' in the basket.
Hope some of this helps.
Al