Charges for no fault visits are not unusual, but if a fault that is not down to you is found then usually no charge.
If they try and charge when finally someone fixed it then you need to challenge the charges.
On the text messages - that is down to chasing for compensation for the fault period, the fixed compensation amounts are not in place just yet.
NOTE: There should be no IP Profile system as this is Sky so why stuck at 25 Mbps throughput is a puzzle again you need to pester Sky.
On going to 39,999 you might the 700 Kbps difference is only a small change in conditions. If the DLM was reset after fault cleared then its sit and wait to see what happens.