what it is you're asking. If you want to know whether you can break your contract because of these outages the answer might be 'yes', but it will depend on the frequency and length of the downtime. Most ISP's have disclaimer clauses in the terms and conditions which cover the possibility of technical faults.
Speed inconsistencies are even more difficult to contest, because all published connection speeds are only a guide to the maximum you can expect. Downstream speeds will usually be lower than the published maximum, and will sometimes be much lower, depending on contention, and other factors on the internet.
You can always switch to another ISP, but don't make the assumption that the grass will be greener on that side of the fence. It might be, but there's no guarantee. One of the reasons I stick steadfastly to BT for my broadband services is that they have consistently provided a first-class service over the years. They aren't the cheapest provider around, but in my case money isn't everything - I need reliability and that's what I get.