my first cake was a red velvet with decorators cream cheese(from this site), and once i put the fondant on i noticed it was still lumpy after i smothed out the fondant and the icing didnt really crust and it was coming out the bottom of cake while applying fondant.

my second cake was a chocolate cake with a strawberry smbc filling and a not-to-sweet buttercream(from this site) for the outside. i set in fridge for 24hrs and it was till tacky, i couldnt use the viva smoothing method(which i wanted to try). i tried to smooth as best as i could but had the same issues as my fist cake. after fondant it was lumpy and it started melting?(was oozing out the bottom)

what am i doing wrong? please help with ideas or a tested true bc that will help me with my issues?

I've had both of these issues before. 1 thing I was doing was putting too thick of a layer of icing under my fondant. I now just do a thin coat of crusting buttercream, once crusted I use the viva method and cover. My 2nd issue was I was rolling my fondant too thin. I now use the thickness a cake board to gauge how thick to roll my fondant. My 3rd issue was my buttercream recipe, I was using too much butter and liquid and the moisture and grease was preventing it from crusting. I now use either the buttercream recipe I have on my blog, or sugar shacks butter cream recipe that you can find on here and it works great!
hope this helps