Unacceptable service

Good morning. It's been since last year February that we have been consistently calling telkom customer service, hotline and head office with this same issue. Ever since telkom came to our house and cancelled one of our lines we had internet issues and we have not had many prior to that. There have been almost 40 telkom staff that have come in and out but on a monthly for the past year since we experience issues with the internet and we religiously pay the account but still this pathetic service remains, we have to load extra bundles on our devices (that telkom does not refund us on) and we explicitly tell them that we need it for emails and documents for our church charity but still with no care the issue remains. We have FINALLY been contacted by some manager named Sandile on last Friday and have been promised that by the following Monday our issue will have been resolved, two of the men came and promised to come back to commit to fixing the issue but have failed to do so. This service we cannot tolerate any longer because we are paying customers and this is unacceptable we called asking for a settlement figure but was told they cannot assist with one and neither will the telkom branch, is this justifiable for us not to pay the next installment unless they come fix it or we just move to a different internet provider because this not fair to the customer yet we have been paying for this type of service. Please assist as we are fed up. Thank you