One thing that I learned over the years working in IT environment: As far as providing excellent services to your customers, you can try to be perfect, but you are limited by the products and services you are getting from your vendors.
For example: your users complain desktop system crashes after overnight automatic OS update. Obviously it's the vendor's problem, but you are responsible for it as far as your users are concerned. In other words, it impacts your SLA and customer satisfaction. Some of the limitations can be overcome and risks can be mitigated via redundancy, disaster recovery, backup, testing etc, while others are not as simple.
An area of particular interesting is cloud computing. If you use a 3rd party cloud app serving your customers, and the provider's SLA is basically the best you can achieve if you are perfect, and your brand, customer satisfaction, loyalty can be damaged as a result of the vendor's inability. One would argue that even if the app is in house, you are subject to down time. It is true if we are talking about hardware issue, but there are a lot of human delays that don't even account in SLA. For instance, you use a 3rd party cloud based customer service software, your users are complaining to you the app does not recognize correct passwords, you will need to contact the vendor. The provider may take days to resolve the problem depending on the skill level of the support personnel at the vendor, yet the vendor may not violate SLA at all so long as they keep interacting with you. Imaging the app is your e-commerce app.
Be aware, your cloud vendor is liability to your customer satisfaction.
Hubcase automates issue escalation and interaction between you and your vendors or partners, and also offers free SaaS Service Desk.