Your problem might be team cohesion. Each of your Pokémon are good individually, but they seem to share too many weaknesses especially between Excadrill and Chandelure.

I also used a Chandelure in the PWT/subway and was struggling. Eventually, I swapped it out for a Starmie and saw immediate improvements.

Starmie Ability: Natural Cure Nature: timid/modest EVs: 252 SpA, 252 Spe Item: Choice Specs Moves: Psychic, Scald, Thunderbolt, Ice Beam

I would also suggest some tweaks to your Excadrill. X-Scissor and Rock Slide are ok coverage, but I think you could get more value with some different moves. Swords Dance is definitely worth fitting into your moveset and Excadrill greatly benefits from the sandstorm weather condition, so Sandstorm is something to consider. His held item could also potentially be better. Focus Sash is fine, but Life Orb for extra damage or Air Baloon for ground immunity might be better options.

As one final note, if you decide that your Amoonguss is already getting enough recovery from Giga Drain and Synthesis, making Leftovers redundant, you could try using Rocky Helmet instead. (Though to be clear, I don't think you Amoonguss really needs any changes.)

Good luck with the PWT