Well, being an outdated technology, you may not be able to get a better speed than that prevailing as of now from BSNL EVDO. If you want better speeds, you definitely need to look for the better alternatives.
The actual alternative will depend on your location and the coverage in your area. You may opt for any good 3G/4G connection that can provide a faster speed.
BSNL EVDO excels in its economical plans. You get a truly unlimited plan with them.
As for your query on returning the EVDO, you may need to contact your local office of BSNL. There are no specific instructions available on their website. But, like most of the services, it must have a standard procedure. You may contact the local BSNL customer care centre.
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