How to troubleshoot this bandstop filter circuit....?
This is not how you design a band-stop filter.


First start with specs for Pass-band -3dB points and ripple
Next define acceptable Band-stop rejection thresholds at lower and upper f.
The slope of these above specs implies n required for nth order LC filter required or RC filter required. ( e.g. cauer, chebyshev active filter IC)
Alternative way is design n high Q, RC notch (twin-T)filters, cascaded, but this is suboptimal
you cannot simply cascade 1st order LPF and expect good band-stop results by trial and error then take difference of LPF and BPF
reason is; 2nd order filter is up to 12dB/octave and only 6dB in 1st octave and your f2-f1 spread is only 4 octaves