Cracking/Creaking noise when pedalling hard or standing on a pedal
Where did you buy it? I'm guessing that your local bike store, unless they were the place where you purchased it, probably has little if any interest in working on the bike, unless you are willing to pay a good amount.
I looked at the specs on this bike and the crank/bottom bracket is not precisely described. Pictures would be helpful, but if the bottom bracket has cups that attach it-- the manufacturer only seems to sell that kind-- my guess would be, you need to remove the cups, put some anti-seize compound on the threads, and torque them down properly.
I had a creak like this on my bike, which was assembled in Taiwan, and upon disassembly, found the BB cups were barely lubricated with a minuscule amount of some all-purpose grease. I put in a proper amount of anti-seize compound, reassembled to spec, and all was well, no more creak.