Slow speed

I am a new customer and I opted for the slowest speed available because I did not think I would need it as I only have a phone iPad and Netflix. I am wondering if the slow speed I have chosen is responsible for these issues, I did not have them with my previous Wi-Fi provider, but that service was at a much higher speed. If necessary to correct this problem, I may have to increase the speed of my service. Please let me know what I need to do.