Colvin Plumbing Inc.

I have been experiencing pretty loud water hammering issue through out the house for quite sometime and decided to call a couple plumbing company to see if they could resolve it quickly or give me an estimate for any major repair that needs to be done.
Colvin plumbing was the first to respond to my call and the plumber showed up prompted.
We discussed the issue and they were able to resolve the hammering partially with piping that they had easy access to.
When we were investigating the hammering on the upper floor, they were testing out the shutoff valve for my sink and toilet. The conclusion was that a major repair required for them to cut into the wall. I was not ready for the job so asked them to provide a quick quote and will get back to them. I also specifically asked about the invoice for the partial solution and the plumber showed me the invoice while they were still in my house.
Service issue:
It turned out that after the plumber invested the upstairs washroom, they did not turn the shut off for my toilet. However, the tank was still slowly filling up through a very tight opening. For 3 nights in a row, 10 seconds after we used the toilet (I presume after the tank was filled up) the pipping behind the wall was making very loud noise that was waking up everyone in the house (at 3 AM) and the beighburs (we are in a townhouse). We are not plumbers so we had no clue what was causing this but was somehow about to turn it off temporary by turning on and off the shower in the same bathroom.
This went away after we tried turning on and off the different shutoff valve and realized that the one behind the toilet was barely open.
Billing issue:
After the plumber left, I received an email from the company with the estimate of the work to be done if I were to open up walls. However, the invoice never came, part of me thought this was a free consultation because I did try to compare pricing with another plumbing company and they didn't charge me anything for this initial assessment.
A couple weeks later, I got a call from the company asking me to pay the invoice, at which point I told them I ever got one. They send me the invoice after the call and the email address it was suppose to go to.
Then a couple of weeks later again and I got another call from the company asking me to pay the invoice. I have confirmation from my bank statement that the invoice was paid on the day I got the first call. They looked into the issue and told me that they gave me the wrong email address for the e transfer and I had to deal with my bank to cancel the original payment just so I can pay them again.

I hope this is the end of my experience but I DO NOT recommend their service given all the sloppiness all around from the service and office personnel. You never what kind of issue you might get into with this lack of attention to detail.