Does any royal mail staff here know what your monitored on postage timeframe

As the title says, were currently writing the our MP but want to make sure we get all the facts right, obviously not blaming staff but the company has gone to crap, we've had so many packages take 2+ weeks to arrive, even tracked 24/48 have been taking 10 plus times in multiple instances.

I'm trying to write to my local MP and i have all the tracking information listed too to provide to them but what actual stats are royal mail monitored on. As looking online it only seems to be 1st class and 2nd class by the data i can find or is tracked included?