Ip changed, low speed

hi to everyone,
i have access to an access point near my house, which gets internet service from an ISP here in my country. someone i know was testing his skills and disconnected me, from a comp with internet provided by another ISP (probably blocked my external ip) and assigned me another ip (or it had probably changed by default after blocking my current one, don't know). after that (the next day) my internet speed has dropped a lot (only the downloading speed, as for the uploading speed it's the same as before). now my question is, is this happening because of the ip changing? i know ip-s can change (it just changed the last 2 groups of digits again a few moments ago, but still have low downloading speed). i'm affraid that some ports, in the access point center, are limiting the speed for an interval fo ip-s, where my current ip may be included. my knowledges are limited so i may be wrong... what do you think is causing this issue? what step should i take to learn more about on the problem? any kind of suggestion is appreciated.
greetings