Dropped Calls, and “NO SERVICE” in an area that used to have GREAT signal

I’ve complained about this “No Service” issue before, back on June 28, someone from AT&T contacted me, I let them know the situation in detail, and of course, I never heard back.  Seems to be a growing trend that the bigger the company gets, the more likely they tend to just brush off customer issues.  Today the “No Service” issue is especially bad.  So, I’m reposting this until I get an answer.

I work in the 75114 zip code, just southeast of Dallas, but reside in Dallas.  My boss, several employees, and I, have AT&T Wireless.  For years the signal worked fine in this area.  Now all of a sudden, in this area, Crandall, TX, everyone with AT&T has problems with their phones saying "No Signal" at least a few times a day.  We all have different phones, and different accounts.  Our salesmen are missing calls from customers because of the “No Service” issue.  Other times we just get one little dot on the LTE, sometimes 2 or 3 if we are lucky.  My boss is particularly upset that calls have been dropping more than they ever had.  I've been using ATT's "Mark the Spot" app for several months to report issues in this area, but it doesn't make a difference.  I think they just have it to pacify customers.  What is the deal, AT&T?    How did service get worse?  More people moving to the area?  How are you planning to remedy this?  Literally, your headquarters is just 21 miles away, and this shouldn't be happening.   How about doing some good with those massive tax cuts by improving service?  We'd all appreciate it!