I'm facing serious problems with my site's appearance on Google. I recently added different service locations to the end of the page descriptions, Google seems to have trimmed all of my descriptions to 145 characters to not include that. My descriptions have a max length of 288 characters. Also, Google is crawling my site (at a very slow pace) but is not updating any pages in the index. I resubmitted my sitemap many times and fetched sitemap to let Google crawl to linked pages, but that seems to do nothing. What can I do to resolve this?
If Google shows a thumbnail on the left side of your description in its SERPs, then you will get to display less text in your description. A good thumbnail will likely have a higher clickthrough rate than the trimmed text.
In order to get your trimmed text into your description, you will either have to put it before other text so that it displays, or you will have to modify your meta/schema so that you don't have a thumbnail.
Google will only be able to update the description of your pages once it recrawls them. Unfortunately, there's no good method to convince Googlebot to crawl more of your pages. Google only has so much server capacity to crawl the web, and it selects which websites get crawled more frequently than others.
If you want Google to recrawl the pages on your site, then your best bet is to convince Google that your site should be crawled. This can happen if it discovers highly trusted links pointing to your site, or if it falls in love with your site's content.