[Ask] Cant get from arena 6 to 7

Been in arena 6 for awhile now. Made it to 7 a few times but then the game gives me level 10s while Im a level 8. I dont have poison Giant Skelly or Arena 7 cards but I do have the Miner....Any good decks I can use. Currently Using

Goblin Barrel

Valkyre

Miner

Minions

Rocket

Archers

Baby Dragon

Spear Goblins

This deck got me from Arena 2 til now with either Giant/Miner as tank but not working anymore

All my commons are level 8 rares are 5/6 and epics are scattered 1-3

Thank you any help will be appc.