Probably would have gotten a quicker by asking here.
If you post your modem connection stats (Sync Rate, Signal to Noise Ratio etc - from the modem homepage, not speedtest), then we can let you know if there should be something that can be done to fix it, or whether it looks like a combination of distance from exchange &/or congestion at the exchange.
Also, would be good to know if your landline sounds clear, and any speedtest results (different to modem stats - modem stats give how it is connected to the exchange, speedtest tells how much data is typically throughput from an external source).