Just a series of more or less minor things that have led to a general dislike of them. I used to have dialup and webspace with them for the business, ended up getting rid of it when their customer service levels tanked. Oh, and they were handling my DNS registration for me, they were supposed to register it for 5 years and only registered it for one. I told them I was cancelling the service by phone and by fax, and I kept getting bills from them for almost a year afterward.
With the cell phones, I asked about upgrading my phone and found out that the only way to upgrade it is to re-sign for a new contract (not necessarily at the same rate I have now).
We decided to get another phone number for our spin-off business, and after consulting their sales office by phone decided on the option that only goes to voicemail (since we already have 3 lines going into the house). Got all the info on the phone, had to go in to a service centre to get it taken care of. Told the sales guy exactly what we wanted, he filled out the paperwork for something entirely different. When I reviewed it and pointed out his error he gave me the heavy sigh, sounded disgusted and told me that I should have told him that in the first place. He then proceeded to misspell both the name and the address. Found out later that he didn't correct the address (after we told him) because the bills went to the wrong place for 3 months and we were getting hit with late charges (which they did take off).
We had to pay a $200 deposit on the new line, which we were told would be automatically refunded after 6 months. After 7 months I called them and they had no idea what I was talking about. It took about a week but someone eventually did figure out it, and told me that it would take another month before they could issue the refund. It took about a month and a half.
I guess actually it all began a few years prior to that when we had them come out to do something with the wiring (can't remember what) and I was chastised because the wiring for the phone lines was incorrect and dangerous. Had to point out to them that THEY had done the wiring, not me.
Oh, and one of my friends has DSL through them, she was told how long it would take before the install and it took almost a month longer than that. She got the same runaround I did with the refund - called them, someone was supposed to call back that day and never did. Each and every day it was the same routine.
So it's just seems that at every turn I get really bad customer service from them, which has led me to try and steer away from them whenever possible. I use YAK for my long distance (which is saving me a lot, despite the fact that I had the unlimited-capped-Canada-long-distance-plan-thingie), I use Shaw for my internet, and if I could use someone else for my phone service I would. And I really don't like that I've come to feel this way about MTS, considering that I own shares of the company.