Poor and bad signal

We got a rain Sim card which we activated last month after trialing for 7 days and the signal was the best. We then took the option to take an uncapped data option for over R400 a month. Their signal was the best and before we took it we checked the coverage in our area Brentwood Park and it was great however for the past two weeks signal has been worse than poor. We cannot call them because they are not taking calls so we must email but no one is helping and I see it's a lot of people that are complaining.