Trademarks are classified by "Goods and Services". A bus company is clearly different from a mobile app. A mobile app (Instagram) is clearly the same as a mobile app (Bolt). For the purposes of trademarking, the similarity of a "mobile voice and messaging" app and a "mobile photo sharing" app is not quite as clear. I'm sure some lawyers would be happy to help clear it up.

So, while I get your intention, that's not how trademarks work. If Bolt doesn't have a trademark, they should stop complaining.