It is totally appropriate to ask for feedback if you have no relationship to the company.
While I do not have direct experience with this company, I did a quick search on them.
Their copyright notice says they've been in business since 2005. A quick whois check says the domain was registered in July 2006. Archive.org's first record for the company is in May 2007.
Their pricing provides for major overselling. They have to pack clients in larger numbers per machine just to be able to pay for it (even if they are earning something off $0.50/mo plan after merchant transaction fees are deducted from them). They might end up with too many customers, too few resources to help them and the overall service quality is going down. Its a classic scenario, but I am not saying this is what is happening with this particular company.
They also have an unlimited plan. Unlimited is a known lie (have you ever seen an unlimited hard drive?) and they choose to lie to their customers, so what does that tell you?
I would highly suggest searching the web for "company-name review", "company-name feedback" to get some insight into what other customers might be saying. Keep in mind that a lot of companies have negative reviews from time to time (customers tend to only complain and not praise in their majority), so you have to filter through all reviews to get a feeling for what the service is like and how the company is dealing with problems that arise.