Since about 1998, I manage telephone and computer networks for about 150 customers.
My company may not be compared with big telcos like Deutsche Telekom or Vodafone: I bundle several customers in a building (between about 8 and 40 apartments, more would be no problem) and provide phone and internet service at a very low monthly rate (18 EUR or less) with better service than the big players. I am close to the customer and may be able to address their individual demand much better and more efficiently than the standard products the big telcos provide. Unlike individual families or small or medium-sized businesses, I am able to assess the market and choose the best and least expensive means of providing service to them.
However, I am only able to help if there is already a common network inside your building. Because I have been electrical planner for some years in our district, I have been often in the favourable situation to plan the networks that I manage. If you're in doubt if my portfolio might solve one or two of your problems, drop me an email please!
Should you just be in search of a standard "no-frills" provider for private use or a small company, I'd recommend that you consider Easybell - for medium business it might still be a good option to chose Deutsche Telekom as your provider. I am not in any way affiliated to either company.