Spark Post Message Systems, Inc. rude, disrespectful, poor customer service, unhelpful, extremely slow, ignored me, didn't care, Internet

I emailed SparkPost Customer Service, because one of my secondary domains was rejected by their system.
I already had one of my sub-domains approved, and was preparing SMTP infrastructure for one of my others.

Once it was rejected by the system, I was given no reason why, or opportunity to correct the problem.
It was simply stated that I needed to contact support.

It took many hours for support to reply to me, and it turned out that they were discriminating the content of my website.
They did not feel that I had enough content, which makes no sense at all.

No other SMTP company tries to regulate their customers website content.
My domain also has an SSL certificate, meaning that my identity is 100% verified, and my site is secure.

On top of that, I complied with all other requirements that Spark Post has, which are much more numerable than any other company on the market.
I tried to explain to the company that I couldn't install my script until I setup the SMTP Relay system.

The company didn't care, and they were extremely rude, and slow to respond over a 3-day period.
Some of the comments made by the support staff were very condescending over the course of about 15 emails exchanged.

I contacted their abuse department, which took more than a day to get back to me.
They replied way too late, after I had asked to file an official complaint, and they said that they were sorry I decided to leave their service.

Then, the said they were going to terminate my account, as a result of the fact I was going to leave them.
Completely unprofessional behavior.

Three whole days of my time was wasted on their platform, and they had no one in their system that I could contact for any real support, or accountability.
I am extremely upset about this exchange, and would never-ever recommend this company to any of my professional marketing colleagues in the future.