toba bike gear shifting issue
I purchased an e-bike (tobabikes.com) and I'm having problems with the gear shifting. Shifting from 2nd to 1st is not reliable - the chain keeps getting stuck. And this may happen in a downward slope.
The pedal is blocked from moving forward and I have to stop and get off the bike and after a while walking with the bike, I can get back on and the pedal moves forward. 
When I'm not so lucky, the chain becomes loose. The rear of this bike is too heavy (with motor and battery) to lift and try to get the chain back on my own. I cannot fix it until I get somebody to help me, which is usually my husband who has to drive to where I'm stranded.
I took the bicycle back to the store and I quickly reproduced the problem in front of them (riding it downhill). The person who sold it to me, looked at it and said the rivet is defective, and cannot be fixed and I can only ride on 1x7 or 2x7 or shift first from 2x8 down to 2x7 before going to 1x7.
Not being satisfied with his explanation, as I've never had this problem with previous bikes, including my recumbents, I decided to write the bicycle company.
He basically agreed with the Bike Shop salesperson:
...avoid riding both gears which were opposed (small gear on the back and small gear on the front)
I can confirm, what they (bike shop salesperson) said was right. Having your chain crossed like this may damage the derailleur and the sprockets faster and also give a bad shifting.
This is not specific to the Toba bike, it’s the same situation for every bike on the market.
Here is a draw of shifting that you should avoid:
It’s always better to have your chain as straight as possible from back to front gears.
As a distributor, we don’t provide direct service on products sold, it’s the bike store’s job to fix the situation.
I'm not a bike mechanic, and this has been boggling my mind. So I'm exposing this here to hopefully get some answers from more knowledgeable bike mechanics/experts.
Thanks for reading.
Denise.