Pump problems

I have a Medtronic MiniMed pump now for 2 1/2 years. Hate it! I think I've said that before and nothing has changed. I get an alarm message of "No Delivery" at least once a month, usually more. I get great big bruises surrounding the infusion site entry at least once a week. I will have pain generating from a new site at least twice a month. This past fall I had 3 No Delivery in one day and no problem could be found. I ended up getting a new pump out of that and this new one has done the same thing once. I swear that on the days I need to change out an infusion set, my BG readings will be very, very high. Having said all this, my doctor, my nurse, the Medtronic "helper", none of these have any advice. Have any of you had similar problems? Just so I know I am not going crazy.